Context Navigation

← Previous Change
Next Change →

make.info-1

Timestamp:

Sep 15, 2006, 4:30:32 AM (19 years ago)

Author:

bird

Message:

Load make-3.81/ into vendor/gnumake/current.

File:

: 1 edited

vendor/gnumake/current/doc/make.info-1 (modified) (202 diffs)

Legend:

: Unmodified
: Added
: Removed

vendor/gnumake/current/doc/make.info-1

-              r152
+              r501
+This is make.info, produced by makeinfo version 4.6 from make.texi.
+This is make.info, produced by makeinfo version 4.8 from make.texi.
+   This file documents the GNU `make' utility, which determines
+automatically which pieces of a large program need to be recompiled,
+and issues the commands to recompile them.
+   This is Edition 0.70, last updated 1 April 2006, of `The GNU Make
+Manual', for GNU `make' version 3.81.
+   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
+, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006 Free Software
+Foundation, Inc.
+     Permission is granted to copy, distribute and/or modify this
+     document under the terms of the GNU Free Documentation License,
+     Version 1.2 or any later version published by the Free Software
+     Foundation; with no Invariant Sections, with the Front-Cover Texts
+     being "A GNU Manual," and with the Back-Cover Texts as in (a)
+     below.  A copy of the license is included in the section entitled
+     "GNU Free Documentation License."
+     (a) The FSF's Back-Cover Text is: "You have freedom to copy and
+     modify this GNU Manual, like GNU software.  Copies published by
+     the Free Software Foundation raise funds for GNU development."
 INFO-DIR-SECTION GNU Packages
 …
 END-INFO-DIR-ENTRY
+   This file documents the GNU Make utility, which determines
+File: make.info,  Node: Top,  Next: Overview,  Prev: (dir),  Up: (dir)
+GNU `make'
+**********
+This file documents the GNU `make' utility, which determines
 automatically which pieces of a large program need to be recompiled,
 and issues the commands to recompile them.
+   This is Edition 0.61, last updated 02 May 2003, of `The GNU Make
+Manual', for `make', Version 3.81.
+   Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
+, 1999, 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
+   Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
+Texts.  A copy of the license is included in the section entitled "GNU
+Free Documentation License".
+File: make.info,  Node: Top,  Next: Overview,  Prev: (dir),  Up: (dir)
+Make
+****
+The GNU `make' utility automatically determines which pieces of a large
+program need to be recompiled, and issues the commands to recompile
+them.
+   This edition of the `GNU Make Manual', last updated 02 May 2003,
+documents GNU `make' Version 3.81.
+   This manual describes `make' and contains the following chapters:
+   This is Edition 0.70, last updated 1 April 2006, of `The GNU Make
+Manual', for GNU `make' version 3.81.
+   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
+, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006 Free Software
+Foundation, Inc.
+     Permission is granted to copy, distribute and/or modify this
+     document under the terms of the GNU Free Documentation License,
+     Version 1.2 or any later version published by the Free Software
+     Foundation; with no Invariant Sections, with the Front-Cover Texts
+     being "A GNU Manual," and with the Back-Cover Texts as in (a)
+     below.  A copy of the license is included in the section entitled
+     "GNU Free Documentation License."
+     (a) The FSF's Back-Cover Text is: "You have freedom to copy and
+     modify this GNU Manual, like GNU software.  Copies published by
+     the Free Software Foundation raise funds for GNU development."
 * Menu:
 …
                                   with another makefile.
 * Reading Makefiles::           How makefiles are parsed.
+* Secondary Expansion::         How and when secondary expansion is performed.
 Writing Rules
 …
 * Phony Targets::               Using a target that is not a real file's name.
 * Force Targets::               You can use a target without commands
                                   or prerequisites to mark other
                                   targets as phony.
+                                  or prerequisites to mark other targets
+                                  as phony.
 * Empty Targets::               When only the date matters and the
                                   files are empty.
 …
 Writing the Commands in Rules
+* Command Syntax::              Command syntax features and pitfalls.
 * Echoing::                     How to control when commands are echoed.
 * Execution::                   How commands are executed.
 …
 * Sequences::                   Defining canned sequences of commands.
 * Empty Commands::              Defining useful, do-nothing commands.
+Command Syntax
+* Splitting Lines::             Breaking long command lines for readability.
+* Variables in Commands::       Using `make' variables in commands.
+Command Execution
+* Choosing the Shell::          How `make' chooses the shell used
+                                  to run commands.
 Recursive Use of `make'
 …
 * Text Functions::              General-purpose text manipulation functions.
 * File Name Functions::         Functions for manipulating file names.
+* Conditional Functions::       Functions that implement conditions.
 * Foreach Function::            Repeat some text with controlled variation.
-* If Function::                 Conditionally expand a value.
 * Call Function::               Expand a user-defined function.
 * Value Function::              Return the un-expanded value of a variable.
 * Eval Function::               Evaluate the arguments as makefile syntax.
 * Origin Function::             Find where a variable got its value.
+* Flavor Function::             Find out the flavor of a variable.
 * Shell Function::              Substitute the output of a shell command.
 * Make Control Functions::      Functions that control how make runs.
 …
 * Chained Rules::               How to use a chain of implicit rules.
 * Pattern Rules::               How to define new implicit rules.
 * Last Resort::                 How to defining commands for rules
                                   which cannot find any.
+* Last Resort::                 How to define commands for rules which
+                                  cannot find any.
 * Suffix Rules::                The old-fashioned style of implicit rule.
 * Implicit Rule Search::        The precise algorithm for applying
 …
 * Archive Symbols::             How to update archive symbol directories.
-Makefile Conventions
-* Makefile Basics::             General Conventions for Makefiles
-* Utilities in Makefiles::      Utilities in Makefiles
-* Command Variables::           Variables for Specifying Commands
-* Directory Variables::         Variables for Installation Directories
-* Standard Targets::            Standard Targets for Users
-* Install Command Categories::  Three categories of commands in the `install'
-Copying This Manual
 File: make.info,  Node: Overview,  Next: Introduction,  Prev: Top,  Up: Top
 Overview of `make'
 ******************
+Overview of `make'
+********************
 The `make' utility automatically determines which pieces of a large
 …
    GNU `make' conforms to section 6.2 of `IEEE Standard 1003.2-1992'
 (POSIX.2).
+(POSIX.2).
    Our examples show C programs, since they are most common, but you
 …
 File: make.info,  Node: Reading,  Next: Bugs,  Prev: Preparing,  Up: Overview
 How to Read This Manual
 =======================
+.1 How to Read This Manual
+===========================
 If you are new to `make', or are looking for a general introduction,
 …
 File: make.info,  Node: Bugs,  Prev: Reading,  Up: Overview
 Problems and Bugs
 =================
+.2 Problems and Bugs
+=====================
 If you have problems with GNU `make' or think you've found a bug,
 …
 File: make.info,  Node: Introduction,  Next: Makefiles,  Prev: Overview,  Up: Top
 An Introduction to Makefiles
 ****************************
+An Introduction to Makefiles
+******************************
 You need a file called a "makefile" to tell `make' what to do.  Most
 often, the makefile tells `make' how to compile and link a program.
+often, the makefile tells `make' how to compile and link a program.
    In this chapter, we will discuss a simple makefile that describes
 …
 Finally, if any source file has been recompiled, all the object files,
 whether newly made or saved from previous compilations, must be linked
 together to produce the new executable editor.
+together to produce the new executable editor.
 * Menu:
 …
 File: make.info,  Node: Rule Introduction,  Next: Simple Makefile,  Prev: Introduction,  Up: Introduction
 What a Rule Looks Like
 ======================
+.1 What a Rule Looks Like
+==========================
 A simple makefile consists of "rules" with the following shape:
 …
 File: make.info,  Node: Simple Makefile,  Next: How Make Works,  Prev: Rule Introduction,  Up: Introduction
 A Simple Makefile
 =================
+.2 A Simple Makefile
+=====================
 Here is a straightforward makefile that describes the way an executable
 …
              cc -o edit main.o kbd.o command.o display.o \
                         insert.o search.o files.o utils.o
      main.o : main.c defs.h
              cc -c main.c
 …
 We split each long line into two lines using backslash-newline; this is
 like using one long line, but is easier to read.
+like using one long line, but is easier to read.
    To use this makefile to create the executable file called `edit',
 …
 prerequisites.  These shell commands say how to update the target file.
 A tab character must come at the beginning of every command line to
 distinguish commands lines from other lines in the makefile.  (Bear in
+distinguish command lines from other lines in the makefile.  (Bear in
 mind that `make' does not know anything about how the commands work.
 It is up to you to supply commands that will update the target file
 properly.  All `make' does is execute the commands in the rule you have
 specified when the target file needs to be updated.)
+specified when the target file needs to be updated.)
    The target `clean' is not a file, but merely the name of an action.
 …
 called "phony targets".  *Note Phony Targets::, for information about
 this kind of target.  *Note Errors in Commands: Errors, to see how to
 cause `make' to ignore errors from `rm' or any other command.
+cause `make' to ignore errors from `rm' or any other command.
 File: make.info,  Node: How Make Works,  Next: Variables Simplify,  Prev: Simple Makefile,  Up: Introduction
 How `make' Processes a Makefile
 ===============================
+.3 How `make' Processes a Makefile
+===================================
 By default, `make' starts with the first target (not targets whose
 names start with `.').  This is called the "default goal".  ("Goals"
+are the targets that `make' strives ultimately to update.  *Note
+Arguments to Specify the Goals: Goals.)
+are the targets that `make' strives ultimately to update.    You can
+override this behavior using the command line (*note Arguments to
+Specify the Goals: Goals.) or with the `.DEFAULT_GOAL' special variable
+(*note Other Special Variables: Special Variables.).
    In the simple example of the previous section, the default goal is to
 …
 not exist, or if any of the object files are newer than it.  If an
 object file was just recompiled, it is now newer than `edit', so `edit'
 is relinked.
+is relinked.
    Thus, if we change the file `insert.c' and run `make', `make' will
 …
 File: make.info,  Node: Variables Simplify,  Next: make Deduces,  Prev: How Make Works,  Up: Introduction
 Variables Make Makefiles Simpler
 ================================
+.4 Variables Make Makefiles Simpler
+====================================
 In our example, we had to list all the object files twice in the rule
 …
      objects = main.o kbd.o command.o display.o \
                insert.o search.o files.o utils.o
      edit : $(objects)
              cc -o edit $(objects)
 …
 File: make.info,  Node: make Deduces,  Next: Combine By Prerequisite,  Prev: Variables Simplify,  Up: Introduction
 Letting `make' Deduce the Commands
 ==================================
+.5 Letting `make' Deduce the Commands
+======================================
 It is not necessary to spell out the commands for compiling the
 …
      objects = main.o kbd.o command.o display.o \
                insert.o search.o files.o utils.o
      edit : $(objects)
              cc -o edit $(objects)
      main.o : defs.h
      kbd.o : defs.h command.h
 …
      files.o : defs.h buffer.h command.h
      utils.o : defs.h
      .PHONY : clean
      clean :
 …
 File: make.info,  Node: Combine By Prerequisite,  Next: Cleanup,  Prev: make Deduces,  Up: Introduction
 Another Style of Makefile
 =========================
+.6 Another Style of Makefile
+=============================
 When the objects of a makefile are created only by implicit rules, an
 …
      objects = main.o kbd.o command.o display.o \
                insert.o search.o files.o utils.o
      edit : $(objects)
              cc -o edit $(objects)
      $(objects) : defs.h
      kbd.o command.o files.o : command.h
 …
 File: make.info,  Node: Cleanup,  Prev: Combine By Prerequisite,  Up: Introduction
 Rules for Cleaning the Directory
 ================================
+.7 Rules for Cleaning the Directory
+====================================
 Compiling a program is not the only thing you might want to write rules
 …
 File: make.info,  Node: Makefiles,  Next: Rules,  Prev: Introduction,  Up: Top
 Writing Makefiles
 *****************
+Writing Makefiles
+*******************
 The information that tells `make' how to recompile a system comes from
 …
                                   with another makefile.
 * Reading Makefiles::           How makefiles are parsed.
+* Secondary Expansion::         How and when secondary expansion is performed.
 File: make.info,  Node: Makefile Contents,  Next: Makefile Names,  Prev: Makefiles,  Up: Makefiles
 What Makefiles Contain
 ======================
+.1 What Makefiles Contain
+==========================
 Makefiles contain five kinds of things: "explicit rules", "implicit
 …
 File: make.info,  Node: Makefile Names,  Next: Include,  Prev: Makefile Contents,  Up: Makefiles
 What Name to Give Your Makefile
 ===============================
+.2 What Name to Give Your Makefile
+===================================
 By default, when `make' looks for the makefile, it tries the following
 names, in order: `GNUmakefile', `makefile' and `Makefile'.
+names, in order: `GNUmakefile', `makefile' and `Makefile'.
    Normally you should call your makefile either `makefile' or
 …
 concatenated in the order specified.  The default makefile names
 `GNUmakefile', `makefile' and `Makefile' are not checked automatically
 if you specify `-f' or `--file'.
+if you specify `-f' or `--file'.
 File: make.info,  Node: Include,  Next: MAKEFILES Variable,  Prev: Makefile Names,  Up: Makefiles
 Including Other Makefiles
 =========================
+.3 Including Other Makefiles
+=============================
 The `include' directive tells `make' to suspend reading the current
 …
      include FILENAMES...
+FILENAMES can contain shell file name patterns.
+FILENAMES can contain shell file name patterns.  If FILENAMES is empty,
+nothing is included and no error is printed.
    Extra spaces are allowed and ignored at the beginning of the line,
 …
 than that of somehow appending the prerequisites to the end of the main
 makefile as has been traditionally done with other versions of `make'.
 *Note Automatic Prerequisites::.
+*Note Automatic Prerequisites::.
    If the specified name does not start with a slash, and the file is
 …
 File: make.info,  Node: MAKEFILES Variable,  Next: MAKEFILE_LIST Variable,  Prev: Include,  Up: Makefiles
 The Variable `MAKEFILES'
 ========================
+.4 The Variable `MAKEFILES'
+============================
 If the environment variable `MAKEFILES' is defined, `make' considers
 …
 File: make.info,  Node: MAKEFILE_LIST Variable,  Next: Special Variables,  Prev: MAKEFILES Variable,  Up: Makefiles
 The Variable `MAKEFILE_LIST'
 ============================
+.5 The Variable `MAKEFILE_LIST'
+================================
 As `make' reads various makefiles, including any obtained from the
 …
    If a makefile named `Makefile' has this content:
      name1 := $(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
+     name1 := $(lastword $(MAKEFILE_LIST))
      include inc.mk
      name2 := $(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
+     name2 := $(lastword $(MAKEFILE_LIST))
      all:
              @echo name1 = $(name1)
 …
 File: make.info,  Node: Special Variables,  Next: Remaking Makefiles,  Prev: MAKEFILE_LIST Variable,  Up: Makefiles
+Other Special Variables
+=======================
+GNU `make' also supports a special variable.  Note that any value you
+assign to this variable will be ignored; it will always return its
+special value.
+   The first special variable is `.VARIABLES'.  When expanded, the
+value consists of a list of the _names_ of all global variables defined
+in all makefiles read up until that point.  This includes variables
+which have empty values, as well as built-in variables (*note Variables
+Used by Implicit Rules: Implicit Variables.), but does not include any
+variables which are only defined in a target-specific context.
+.6 Other Special Variables
+===========================
+GNU `make' also supports other special variables.  Unless otherwise
+documented here, these values lose their special properties if they are
+set by a makefile or on the command line.
+`.DEFAULT_GOAL'
+     Sets the default goal to be used if no targets were specified on
+     the command line (*note Arguments to Specify the Goals: Goals.).
+     The `.DEFAULT_GOAL' variable allows you to discover the current
+     default goal, restart the default goal selection algorithm by
+     clearing its value, or to explicitly set the default goal.  The
+     following example illustrates these cases:
+          # Query the default goal.
+          ifeq ($(.DEFAULT_GOAL),)
+            $(warning no default goal is set)
+          endif
+          .PHONY: foo
+          foo: ; @echo $@
+          $(warning default goal is $(.DEFAULT_GOAL))
+          # Reset the default goal.
+          .DEFAULT_GOAL :=
+          .PHONY: bar
+          bar: ; @echo $@
+          $(warning default goal is $(.DEFAULT_GOAL))
+          # Set our own.
+          .DEFAULT_GOAL := foo
+     This makefile prints:
+          no default goal is set
+          default goal is foo
+          default goal is bar
+          foo
+     Note that assigning more than one target name to `.DEFAULT_GOAL' is
+     illegal and will result in an error.
+`MAKE_RESTARTS'
+     This variable is set only if this instance of `make' has restarted
+     (*note How Makefiles Are Remade: Remaking Makefiles.): it will
+     contain the number of times this instance has restarted.  Note
+     this is not the same as recursion (counted by the `MAKELEVEL'
+     variable).  You should not set, modify, or export this variable.
+`.VARIABLES'
+     Expands to a list of the _names_ of all global variables defined
+     so far.  This includes variables which have empty values, as well
+     as built-in variables (*note Variables Used by Implicit Rules:
+     Implicit Variables.), but does not include any variables which are
+     only defined in a target-specific context.  Note that any value
+     you assign to this variable will be ignored; it will always return
+     its special value.
+`.FEATURES'
+     Expands to a list of special features supported by this version of
+     `make'.  Possible values include:
+    `archives'
+          Supports `ar' (archive) files using special filename syntax.
+          *Note Using `make' to Update Archive Files: Archives.
+    `check-symlink'
+          Supports the `-L' (`--check-symlink-times') flag.  *Note
+          Summary of Options: Options Summary.
+    `else-if'
+          Supports "else if" non-nested conditionals.  *Note Syntax of
+          Conditionals: Conditional Syntax.
+    `jobserver'
+          Supports "job server" enhanced parallel builds.  *Note
+          Parallel Execution: Parallel.
+    `second-expansion'
+          Supports secondary expansion of prerequisite lists.
+    `order-only'
+          Supports order-only prerequisites.  *Note Types of
+          Prerequisites: Prerequisite Types.
+    `target-specific'
+          Supports target-specific and pattern-specific variable
+          assignments.  *Note Target-specific Variable Values:
+          Target-specific.
+`.INCLUDE_DIRS'
+     Expands to a list of directories that `make' searches for included
+     makefiles (*note Including Other Makefiles: Include.).
 File: make.info,  Node: Remaking Makefiles,  Next: Overriding Makefiles,  Prev: Special Variables,  Up: Makefiles
 How Makefiles Are Remade
 ========================
+.7 How Makefiles Are Remade
+============================
 Sometimes makefiles can be remade from other files, such as RCS or SCCS
 …
    If you do not specify any makefiles to be read with `-f' or `--file'
 options, `make' will try the default makefile names; *note What Name to
 Give Your Makefile: Makefile Names..  Unlike makefiles explicitly
+Give Your Makefile: Makefile Names.  Unlike makefiles explicitly
 requested with `-f' or `--file' options, `make' is not certain that
 these makefiles should exist.  However, if a default makefile does not
 …
 File: make.info,  Node: Overriding Makefiles,  Next: Reading Makefiles,  Prev: Remaking Makefiles,  Up: Makefiles
 Overriding Part of Another Makefile
 ===================================
+.8 Overriding Part of Another Makefile
+=======================================
 Sometimes it is useful to have a makefile that is mostly just like
 …
      foo:
              frobnicate > foo
      %: force
              @$(MAKE) -f Makefile $@
 …
 File: make.info,  Node: Reading Makefiles,  Prev: Overriding Makefiles,  Up: Makefiles
 How `make' Reads a Makefile
 ===========================
+File: make.info,  Node: Reading Makefiles,  Next: Secondary Expansion,  Prev: Overriding Makefiles,  Up: Makefiles
+.9 How `make' Reads a Makefile
+===============================
 GNU `make' does its work in two distinct phases.  During the first
 …
      IMMEDIATE := IMMEDIATE
      IMMEDIATE += DEFERRED or IMMEDIATE
      define IMMEDIATE
        DEFERRED
 …
 All instances of conditional syntax are parsed immediately, in their
 entirety; this includes the `ifdef', `ifeq', `ifndef', and `ifneq'
+forms.
+forms.  Of course this means that automatic variables cannot be used in
+conditional statements, as automatic variables are not set until the
+command script for that rule is invoked.  If you need to use automatic
+variables in a conditional you _must_ use shell conditional syntax, in
+your command script proper, for these tests, not `make' conditionals.
 Rule Definition
 …
+File: make.info,  Node: Secondary Expansion,  Prev: Reading Makefiles,  Up: Makefiles
+.10 Secondary Expansion
+========================
+In the previous section we learned that GNU `make' works in two
+distinct phases: a read-in phase and a target-update phase (*note How
+`make' Reads a Makefile: Reading Makefiles.).  GNU make also has the
+ability to enable a _second expansion_ of the prerequisites (only) for
+some or all targets defined in the makefile.  In order for this second
+expansion to occur, the special target `.SECONDEXPANSION' must be
+defined before the first prerequisite list that makes use of this
+feature.
+   If that special target is defined then in between the two phases
+mentioned above, right at the end of the read-in phase, all the
+prerequisites of the targets defined after the special target are
+expanded a _second time_.  In most circumstances this secondary
+expansion will have no effect, since all variable and function
+references will have been expanded during the initial parsing of the
+makefiles.  In order to take advantage of the secondary expansion phase
+of the parser, then, it's necessary to _escape_ the variable or
+function reference in the makefile.  In this case the first expansion
+merely un-escapes the reference but doesn't expand it, and expansion is
+left to the secondary expansion phase.  For example, consider this
+makefile:
+     .SECONDEXPANSION:
+     ONEVAR = onefile
+     TWOVAR = twofile
+     myfile: $(ONEVAR) $$(TWOVAR)
+   After the first expansion phase the prerequisites list of the
+`myfile' target will be `onefile' and `$(TWOVAR)'; the first
+(unescaped) variable reference to ONEVAR is expanded, while the second
+(escaped) variable reference is simply unescaped, without being
+recognized as a variable reference.  Now during the secondary expansion
+the first word is expanded again but since it contains no variable or
+function references it remains the static value `onefile', while the
+second word is now a normal reference to the variable TWOVAR, which is
+expanded to the value `twofile'.  The final result is that there are
+two prerequisites, `onefile' and `twofile'.
+   Obviously, this is not a very interesting case since the same result
+could more easily have been achieved simply by having both variables
+appear, unescaped, in the prerequisites list.  One difference becomes
+apparent if the variables are reset; consider this example:
+     .SECONDEXPANSION:
+     AVAR = top
+     onefile: $(AVAR)
+     twofile: $$(AVAR)
+     AVAR = bottom
+   Here the prerequisite of `onefile' will be expanded immediately, and
+resolve to the value `top', while the prerequisite of `twofile' will
+not be full expanded until the secondary expansion and yield a value of
+`bottom'.
+   This is marginally more exciting, but the true power of this feature
+only becomes apparent when you discover that secondary expansions
+always take place within the scope of the automatic variables for that
+target.  This means that you can use variables such as `$@', `$*', etc.
+during the second expansion and they will have their expected values,
+just as in the command script.  All you have to do is defer the
+expansion by escaping the `$'.  Also, secondary expansion occurs for
+both explicit and implicit (pattern) rules.  Knowing this, the possible
+uses for this feature increase dramatically.  For example:
+     .SECONDEXPANSION:
+     main_OBJS := main.o try.o test.o
+     lib_OBJS := lib.o api.o
+     main lib: $$($$@_OBJS)
+   Here, after the initial expansion the prerequisites of both the
+`main' and `lib' targets will be `$($@_OBJS)'.  During the secondary
+expansion, the `$@' variable is set to the name of the target and so
+the expansion for the `main' target will yield `$(main_OBJS)', or
+`main.o try.o test.o', while the secondary expansion for the `lib'
+target will yield `$(lib_OBJS)', or `lib.o api.o'.
+   You can also mix functions here, as long as they are properly
+escaped:
+     main_SRCS := main.c try.c test.c
+     lib_SRCS := lib.c api.c
+     .SECONDEXPANSION:
+     main lib: $$(patsubst %.c,%.o,$$($$@_SRCS))
+   This version allows users to specify source files rather than object
+files, but gives the same resulting prerequisites list as the previous
+example.
+   Evaluation of automatic variables during the secondary expansion
+phase, especially of the target name variable `$$@', behaves similarly
+to evaluation within command scripts.  However, there are some subtle
+differences and "corner cases" which come into play for the different
+types of rule definitions that `make' understands.  The subtleties of
+using the different automatic variables are described below.
+Secondary Expansion of Explicit Rules
+-------------------------------------
+During the secondary expansion of explicit rules, `$$@' and `$$%'
+evaluate, respectively, to the file name of the target and, when the
+target is an archive member, the target member name.  The `$$<'
+variable evaluates to the first prerequisite in the first rule for this
+target.  `$$^' and `$$+' evaluate to the list of all prerequisites of
+rules _that have already appeared_ for the same target (`$$+' with
+repetitions and `$$^' without).  The following example will help
+illustrate these behaviors:
+     .SECONDEXPANSION:
+     foo: foo.1 bar.1 $$< $$^ $$+    # line #1
+     foo: foo.2 bar.2 $$< $$^ $$+    # line #2
+     foo: foo.3 bar.3 $$< $$^ $$+    # line #3
+   In the first prerequisite list, all three variables (`$$<', `$$^',
+and `$$+') expand to the empty string.  In the second, they will have
+values `foo.1', `foo.1 bar.1', and `foo.1 bar.1' respectively.  In the
+third they will have values `foo.1', `foo.1 bar.1 foo.2 bar.2', and
+`foo.1 bar.1 foo.2 bar.2' respectively.
+   Rules undergo secondary expansion in makefile order, except that the
+rule with the command script is always evaluated last.
+   The variables `$$?' and `$$*' are not available and expand to the
+empty string.
+Secondary Expansion of Static Pattern Rules
+-------------------------------------------
+Rules for secondary expansion of static pattern rules are identical to
+those for explicit rules, above, with one exception: for static pattern
+rules the `$$*' variable is set to the pattern stem.  As with explicit
+rules, `$$?' is not available and expands to the empty string.
+Secondary Expansion of Implicit Rules
+-------------------------------------
+As `make' searches for an implicit rule, it substitutes the stem and
+then performs secondary expansion for every rule with a matching target
+pattern.  The value of the automatic variables is derived in the same
+fashion as for static pattern rules.  As an example:
+     .SECONDEXPANSION:
+     foo: bar
+     foo foz: fo%: bo%
+     %oo: $$< $$^ $$+ $$*
+   When the implicit rule is tried for target `foo', `$$<' expands to
+`bar', `$$^' expands to `bar boo', `$$+' also expands to `bar boo', and
+`$$*' expands to `f'.
+   Note that the directory prefix (D), as described in *Note Implicit
+Rule Search Algorithm: Implicit Rule Search, is appended (after
+expansion) to all the patterns in the prerequisites list.  As an
+example:
+     .SECONDEXPANSION:
+     /tmp/foo.o:
+     %.o: $$(addsuffix /%.c,foo bar) foo.h
+   The prerequisite list after the secondary expansion and directory
+prefix reconstruction will be `/tmp/foo/foo.c /tmp/var/bar/foo.c
+foo.h'.  If you are not interested in this reconstruction, you can use
+`$$*' instead of `%' in the prerequisites list.
 File: make.info,  Node: Rules,  Next: Commands,  Prev: Makefiles,  Up: Top
 Writing Rules
 *************
+Writing Rules
+***************
 A "rule" appears in the makefile and says when and how to remake
 …
 * Phony Targets::               Using a target that is not a real file's name.
 * Force Targets::               You can use a target without commands
                                   or prerequisites to mark other
                                   targets as phony.
+                                  or prerequisites to mark other targets
+                                  as phony.
 * Empty Targets::               When only the date matters and the
                                   files are empty.
 …
 File: make.info,  Node: Rule Example,  Next: Rule Syntax,  Prev: Rules,  Up: Rules
 Rule Example
 ============
+.1 Rule Example
+================
 Here is an example of a rule:
 …
 File: make.info,  Node: Rule Syntax,  Next: Prerequisite Types,  Prev: Rule Example,  Up: Rules
 Rule Syntax
 ===========
+.2 Rule Syntax
+===============
 In general, a rule looks like this:
 …
 appear on the line after the prerequisites, with a tab character, or may
 appear on the same line, with a semicolon.  Either way, the effect is
+the same.  *Note Writing the Commands in Rules: Commands.
+   Because dollar signs are used to start variable references, if you
+really want a dollar sign in a rule you must write two of them, `$$'
+(*note How to Use Variables: Using Variables.).  You may split a long
+line by inserting a backslash followed by a newline, but this is not
+required, as `make' places no limit on the length of a line in a
+makefile.
+the same.  There are other differences in the syntax of command lines.
+*Note Writing the Commands in Rules: Commands.
+   Because dollar signs are used to start `make' variable references,
+if you really want a dollar sign in a target or prerequisite you must
+write two of them, `$$' (*note How to Use Variables: Using Variables.).
+If you have enabled secondary expansion (*note Secondary Expansion::)
+and you want a literal dollar sign in the prerequisites lise, you must
+actually write _four_ dollar signs (`$$$$').
+   You may split a long line by inserting a backslash followed by a
+newline, but this is not required, as `make' places no limit on the
+length of a line in a makefile.
    A rule tells `make' two things: when the targets are out of date,
 …
 File: make.info,  Node: Prerequisite Types,  Next: Wildcards,  Prev: Rule Syntax,  Up: Rules
 Types of Prerequisites
 ======================
+.3 Types of Prerequisites
+==========================
 There are actually two different types of prerequisites understood by
 …
 File: make.info,  Node: Wildcards,  Next: Directory Search,  Prev: Prerequisite Types,  Up: Rules
 Using Wildcard Characters in File Names
 =======================================
+.4 Using Wildcard Characters in File Names
+===========================================
 A single file name can specify many files using "wildcard characters".
 …
 simulated by setting the environment variable HOME.
    Wildcard expansion happens automatically in targets, in
+prerequisites, and in commands (where the shell does the expansion).
+In other contexts, wildcard expansion happens only if you request it
 explicitly with the `wildcard' function.
+   Wildcard expansion is performed by `make' automatically in targets
+and in prerequisites.  In commands the shell is responsible for
+wildcard expansion.  In other contexts, wildcard expansion happens only
+if you request it explicitly with the `wildcard' function.
    The special significance of a wildcard character can be turned off by
 …
 File: make.info,  Node: Wildcard Examples,  Next: Wildcard Pitfall,  Prev: Wildcards,  Up: Wildcards
 Wildcard Examples
 -----------------
+.4.1 Wildcard Examples
+-----------------------
 Wildcards can be used in the commands of a rule, where they are expanded
 …
 File: make.info,  Node: Wildcard Pitfall,  Next: Wildcard Function,  Prev: Wildcard Examples,  Up: Wildcards
 Pitfalls of Using Wildcards
 ---------------------------
+.4.2 Pitfalls of Using Wildcards
+---------------------------------
 Now here is an example of a naive way of using wildcard expansion, that
 …
      objects = *.o
      foo : $(objects)
              cc -o foo $(CFLAGS) $(objects)
 …
 File: make.info,  Node: Wildcard Function,  Prev: Wildcard Pitfall,  Up: Wildcards
 The Function `wildcard'
 -----------------------
+.4.3 The Function `wildcard'
+-----------------------------
 Wildcard expansion happens automatically in rules.  But wildcard
 …
      objects := $(patsubst %.c,%.o,$(wildcard *.c))
      foo : $(objects)
              cc -o foo $(objects)
 …
 File: make.info,  Node: Directory Search,  Next: Phony Targets,  Prev: Wildcards,  Up: Rules
 Searching Directories for Prerequisites
 =======================================
+.5 Searching Directories for Prerequisites
+===========================================
 For large systems, it is often desirable to put sources in a separate
 …
 File: make.info,  Node: General Search,  Next: Selective Search,  Prev: Directory Search,  Up: Directory Search
 `VPATH': Search Path for All Prerequisites
 ------------------------------------------
+.5.1 `VPATH': Search Path for All Prerequisites
+------------------------------------------------
 The value of the `make' variable `VPATH' specifies a list of
 …
 File: make.info,  Node: Selective Search,  Next: Search Algorithm,  Prev: General Search,  Up: Directory Search
 The `vpath' Directive
 ---------------------
+.5.2 The `vpath' Directive
+---------------------------
 Similar to the `VPATH' variable, but more selective, is the `vpath'
 …
 File: make.info,  Node: Search Algorithm,  Next: Commands/Search,  Prev: Selective Search,  Up: Directory Search
 How Directory Searches are Performed
 ------------------------------------
+.5.3 How Directory Searches are Performed
+------------------------------------------
 When a prerequisite is found through directory search, regardless of
 …
 File: make.info,  Node: Commands/Search,  Next: Implicit/Search,  Prev: Search Algorithm,  Up: Directory Search
 Writing Shell Commands with Directory Search
 --------------------------------------------
+.5.4 Writing Shell Commands with Directory Search
+--------------------------------------------------
 When a prerequisite is found in another directory through directory
 …
 compilation by implicit rules; we use it here for consistency so it will
 affect all C compilations uniformly; *note Variables Used by Implicit
 Rules: Implicit Variables..)
+Rules: Implicit Variables.)
    Often the prerequisites include header files as well, which you do
 …
 File: make.info,  Node: Implicit/Search,  Next: Libraries/Search,  Prev: Commands/Search,  Up: Directory Search
 Directory Search and Implicit Rules
 -----------------------------------
+.5.5 Directory Search and Implicit Rules
+-----------------------------------------
 The search through the directories specified in `VPATH' or with `vpath'
 …
 File: make.info,  Node: Libraries/Search,  Prev: Implicit/Search,  Up: Directory Search
 Directory Search for Link Libraries
 -----------------------------------
+.5.6 Directory Search for Link Libraries
+-----------------------------------------
 Directory search applies in a special way to libraries used with the
 …
 word in the list will be used.
    The default value for `.LIBPATTERNS' is "`lib%.so lib%.a'", which
+   The default value for `.LIBPATTERNS' is `lib%.so lib%.a', which
 provides the default behavior described above.
 …
 File: make.info,  Node: Phony Targets,  Next: Force Targets,  Prev: Directory Search,  Up: Rules
 Phony Targets
 =============
+.6 Phony Targets
+=================
 A phony target is one that is not really the name of a file.  It is
 …
 Because the `rm' command does not create a file named `clean', probably
 no such file will ever exist.  Therefore, the `rm' command will be
 executed every time you say `make clean'.
+executed every time you say `make clean'.
    The phony target will cease to work if anything ever does create a
 …
    Another example of the usefulness of phony targets is in conjunction
 with recursive invocations of `make' (for more information, see *Note
 Recursive Use of `make': Recursion).  In this case the makefile will
+Recursive Use of `make': Recursion.).  In this case the makefile will
 often contain a variable which lists a number of subdirectories to be
 built.  One way to handle this is with one rule whose command is a
 …
      SUBDIRS = foo bar baz
      subdirs:
              for dir in $(SUBDIRS); do \
 …
 it will do so even if `make' is invoked with the `-k' option, which is
 unfortunate.  Second, and perhaps more importantly, you cannot take
 advantage of the parallel build capabilities of make using this method,
 since there is only one rule.
+advantage of `make''s ability to build targets in parallel (*note
+Parallel Execution: Parallel.), since there is only one rule.
    By declaring the subdirectories as phony targets (you must do this as
 …
      SUBDIRS = foo bar baz
      .PHONY: subdirs $(SUBDIRS)
      subdirs: $(SUBDIRS)
      $(SUBDIRS):
              $(MAKE) -C $@
      foo: baz
 …
      all : prog1 prog2 prog3
      .PHONY : all
      prog1 : prog1.o utils.o
              cc -o prog1 prog1.o utils.o
      prog2 : prog2.o
              cc -o prog2 prog2.o
      prog3 : prog3.o sort.o utils.o
              cc -o prog3 prog3.o sort.o utils.o
 Now you can say just `make' to remake all three programs, or specify as
+arguments the ones to remake (as in `make prog1 prog3').
+arguments the ones to remake (as in `make prog1 prog3').  Phoniness is
+not inherited: the prerequisites of a phony target are not themselves
+phony, unless explicitly declared to be so.
    When one phony target is a prerequisite of another, it serves as a
 …
      .PHONY: cleanall cleanobj cleandiff
      cleanall : cleanobj cleandiff
              rm program
      cleanobj :
              rm *.o
      cleandiff :
              rm *.diff
 …
 File: make.info,  Node: Force Targets,  Next: Empty Targets,  Prev: Phony Targets,  Up: Rules
 Rules without Commands or Prerequisites
 =======================================
+.7 Rules without Commands or Prerequisites
+===========================================
 If a rule has no prerequisites or commands, and the target of the rule
 …
 File: make.info,  Node: Empty Targets,  Next: Special Targets,  Prev: Force Targets,  Up: Rules
 Empty Target Files to Record Events
 ===================================
+.8 Empty Target Files to Record Events
+=======================================
 The "empty target" is a variant of the phony target; it is used to hold
 …
              lpr -p $?
              touch print
 With this rule, `make print' will execute the `lpr' command if either
 source file has changed since the last `make print'.  The automatic
 …
 File: make.info,  Node: Special Targets,  Next: Multiple Targets,  Prev: Empty Targets,  Up: Rules
 Special Built-in Target Names
 =============================
+.9 Special Built-in Target Names
+=================================
 Certain names have special meanings if they appear as targets.
 …
      intermediate).
+`.SECONDEXPANSION'
+     If `.SECONDEXPANSION' is mentioned as a target anywhere in the
+     makefile, then all prerequisite lists defined _after_ it appears
+     will be expanded a second time after all makefiles have been read
+     in.  *Note Secondary Expansion: Secondary Expansion.
+     The prerequisites of the special target `.SUFFIXES' are the list
+     of suffixes to be used in checking for suffix rules.  *Note
+     Old-Fashioned Suffix Rules: Suffix Rules.
 `.DELETE_ON_ERROR'
      If `.DELETE_ON_ERROR' is mentioned as a target anywhere in the
 …
 File: make.info,  Node: Multiple Targets,  Next: Multiple Rules,  Prev: Special Targets,  Up: Rules
 Multiple Targets in a Rule
 ==========================
+.10 Multiple Targets in a Rule
+===============================
 A rule with multiple targets is equivalent to writing many rules, each
 …
           bigoutput littleoutput : text.g
                   generate text.g -$(subst output,,$@) > $@
      is equivalent to
 …
 File: make.info,  Node: Multiple Rules,  Next: Static Pattern,  Prev: Multiple Targets,  Up: Rules
 Multiple Rules for One Target
 =============================
+.11 Multiple Rules for One Target
+==================================
 One file can be the target of several rules.  All the prerequisites
 …
 File: make.info,  Node: Static Pattern,  Next: Double-Colon,  Prev: Multiple Rules,  Up: Rules
 Static Pattern Rules
 ====================
+.12 Static Pattern Rules
+=========================
 "Static pattern rules" are rules which specify multiple targets and
 …
 File: make.info,  Node: Static Usage,  Next: Static versus Implicit,  Prev: Static Pattern,  Up: Static Pattern
 Syntax of Static Pattern Rules
 ------------------------------
+.12.1 Syntax of Static Pattern Rules
+-------------------------------------
 Here is the syntax of a static pattern rule:
 …
      objects = foo.o bar.o
      all: $(objects)
      $(objects): %.o: %.c
              $(CC) -c $(CFLAGS) $< -o $@
 …
      files = foo.elc bar.o lose.o
      $(filter %.o,$(files)): %.o: %.c
              $(CC) -c $(CFLAGS) $< -o $@
 …
 from `foo.el'.
    Another example shows how to use `$*' in static pattern rules:
+   Another example shows how to use `$*' in static pattern rules:
      bigoutput littleoutput : %output : text.g
 …
 File: make.info,  Node: Static versus Implicit,  Prev: Static Usage,  Up: Static Pattern
 Static Pattern Rules versus Implicit Rules
 ------------------------------------------
+.12.2 Static Pattern Rules versus Implicit Rules
+-------------------------------------------------
 A static pattern rule has much in common with an implicit rule defined
 …
 File: make.info,  Node: Double-Colon,  Next: Automatic Prerequisites,  Prev: Static Pattern,  Up: Rules
 Double-Colon Rules
 ==================
+.13 Double-Colon Rules
+=======================
 "Double-colon" rules are rules written with `::' instead of `:' after
 …
 File: make.info,  Node: Automatic Prerequisites,  Prev: Double-Colon,  Up: Rules
 Generating Prerequisites Automatically
 ======================================
+.14 Generating Prerequisites Automatically
+===========================================
 In the makefile for a program, many of the rules you need to write often
 …
 would have to write dozens of such rules in your makefile.  And, you
 must always be very careful to update the makefile every time you add
 or remove an `#include'.
+or remove an `#include'.
    To avoid this hassle, most modern C compilers can write these rules
 …
 makefile, so it can never be considered an intermediate file by implicit
 rule search.  This means that `make' won't ever remove the file after
 using it; *note Chains of Implicit Rules: Chained Rules..
+using it; *note Chains of Implicit Rules: Chained Rules.
    With old `make' programs, it was traditional practice to use this
 …
      %.d: %.c
+             @set -e; rm -f $@; \
               $(CC) -M $(CPPFLAGS) $< > $@.$$$$; \
               sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 …
 *Note Pattern Rules::, for information on defining pattern rules.  The
 `-e' flag to the shell causes it to exit immediately if the `$(CC)'
 command (or any other command) fails (exits with a nonzero status).
+command (or any other command) fails (exits with a nonzero status).
    With the GNU C compiler, you may wish to use the `-MM' flag instead
 …
      sources = foo.c bar.c
      include $(sources:.c=.d)
 …
    Note that the `.d' files contain target definitions; you should be
 sure to place the `include' directive _after_ the first, default target
+sure to place the `include' directive _after_ the first, default goal
 in your makefiles or run the risk of having a random object file become
 the default target.  *Note How Make Works::.
+the default goal.  *Note How Make Works::.
 File: make.info,  Node: Commands,  Next: Using Variables,  Prev: Rules,  Up: Top
+Writing the Commands in Rules
+*****************************
+The commands of a rule consist of shell command lines to be executed one
+by one.  Each command line must start with a tab, except that the first
+command line may be attached to the target-and-prerequisites line with a
+semicolon in between.  Blank lines and lines of just comments may appear
+among the command lines; they are ignored.  (But beware, an apparently
+"blank" line that begins with a tab is _not_ blank!  It is an empty
+command; *note Empty Commands::.)
+Writing the Commands in Rules
+*******************************
+The commands of a rule consist of one or more shell command lines to be
+executed, one at a time, in the order they appear.  Typically, the
+result of executing these commands is that the target of the rule is
+brought up to date.
    Users use many different shell programs, but commands in makefiles
 …
 otherwise.  *Note Command Execution: Execution.
-   The shell that is in use determines whether comments can be written
-on command lines, and what syntax they use.  When the shell is
-`/bin/sh', a `#' starts a comment that extends to the end of the line.
-The `#' does not have to be at the beginning of a line.  Text on a line
-before a `#' is not part of the comment.
 * Menu:
+* Command Syntax::              Command syntax features and pitfalls.
 * Echoing::                     How to control when commands are echoed.
 * Execution::                   How commands are executed.
 …
+File: make.info,  Node: Echoing,  Next: Execution,  Prev: Commands,  Up: Commands
+Command Echoing
+===============
+File: make.info,  Node: Command Syntax,  Next: Echoing,  Prev: Commands,  Up: Commands
+.1 Command Syntax
+==================
+Makefiles have the unusual property that there are really two distinct
+syntaxes in one file.  Most of the makefile uses `make' syntax (*note
+Writing Makefiles: Makefiles.).  However, commands are meant to be
+interpreted by the shell and so they are written using shell syntax.
+The `make' program does not try to understand shell syntax: it performs
+only a very few specific translations on the content of the command
+before handing it to the shell.
+   Each command line must start with a tab, except that the first
+command line may be attached to the target-and-prerequisites line with a
+semicolon in between.  _Any_ line in the makefile that begins with a
+tab and appears in a "rule context" (that is, after a rule has been
+started until another rule or variable definition) will be considered a
+command line for that rule.  Blank lines and lines of just comments may
+appear among the command lines; they are ignored.
+   Some consequences of these rules include:
+   * A blank line that begins with a tab is not blank: it's an empty
+     command (*note Empty Commands::).
+   * A comment in a command line is not a `make' comment; it will be
+     passed to the shell as-is.  Whether the shell treats it as a
+     comment or not depends on your shell.
+   * A variable definition in a "rule context" which is indented by a
+     tab as the first character on the line, will be considered a
+     command line, not a `make' variable definition, and passed to the
+     shell.
+   * A conditional expression (`ifdef', `ifeq', etc. *note Syntax of
+     Conditionals: Conditional Syntax.) in a "rule context" which is
+     indented by a tab as the first character on the line, will be
+     considered a command line and be passed to the shell.
+* Menu:
+* Splitting Lines::             Breaking long command lines for readability.
+* Variables in Commands::       Using `make' variables in commands.
+File: make.info,  Node: Splitting Lines,  Next: Variables in Commands,  Prev: Command Syntax,  Up: Command Syntax
+.1.1 Splitting Command Lines
+-----------------------------
+One of the few ways in which `make' does interpret command lines is
+checking for a backslash just before the newline.  As in normal
+makefile syntax, a single command can be split into multiple lines in
+the makefile by placing a backslash before each newline.  A sequence of
+lines like this is considered a single command, and one instance of the
+shell will be invoked to run it.
+   However, in contrast to how they are treated in other places in a
+makefile, backslash-newline pairs are _not_ removed from the command.
+Both the backslash and the newline characters are preserved and passed
+to the shell.  How the backslash-newline is interpreted depends on your
+shell.  If the first character of the next line after the
+backslash-newline is a tab, then that tab (and only that tab) is
+removed.  Whitespace is never added to the command.
+   For example, this makefile:
+     all :
+             @echo no\
+     space
+             @echo no\
+             space
+             @echo one \
+             space
+             @echo one\
+              space
+consists of four separate shell commands where the output is:
+     nospace
+     nospace
+     one space
+     one space
+   As a more complex example, this makefile:
+     all : ; @echo 'hello \
+             world' ; echo "hello \
+         world"
+will run one shell with a command script of:
+     echo 'hello \
+     world' ; echo "hello \
+         world"
+which, according to shell quoting rules, will yield the following
+output:
+     hello \
+     world
+     hello     world
+Notice how the backslash/newline pair was removed inside the string
+quoted with double quotes (`"..."'), but not from the string quoted
+with single quotes (`'...'').  This is the way the default shell
+(`/bin/sh') handles backslash/newline pairs.  If you specify a
+different shell in your makefiles it may treat them differently.
+   Sometimes you want to split a long line inside of single quotes, but
+you don't want the backslash-newline to appear in the quoted content.
+This is often the case when passing scripts to languages such as Perl,
+where extraneous backslashes inside the script can change its meaning
+or even be a syntax error.  One simple way of handling this is to place
+the quoted string, or even the entire command, into a `make' variable
+then use the variable in the command.  In this situation the newline
+quoting rules for makefiles will be used, and the backslash-newline
+will be removed.  If we rewrite our example above using this method:
+     HELLO = 'hello \
+     world'
+     all : ; @echo $(HELLO)
+we will get output like this:
+     hello world
+   If you like, you can also use target-specific variables (*note
+Target-specific Variable Values: Target-specific.) to obtain a tighter
+correspondence between the variable and the command that uses it.
+File: make.info,  Node: Variables in Commands,  Prev: Splitting Lines,  Up: Command Syntax
+.1.2 Using Variables in Commands
+---------------------------------
+The other way in which `make' processes commands is by expanding any
+variable references in them (*note Basics of Variable References:
+Reference.).  This occurs after make has finished reading all the
+makefiles and the target is determined to be out of date; so, the
+commands for targets which are not rebuilt are never expanded.
+   Variable and function references in commands have identical syntax
+and semantics to references elsewhere in the makefile.  They also have
+the same quoting rules: if you want a dollar sign to appear in your
+command, you must double it (`$$').  For shells like the default shell,
+that use dollar signs to introduce variables, it's important to keep
+clear in your mind whether the variable you want to reference is a
+`make' variable (use a single dollar sign) or a shell variable (use two
+dollar signs).  For example:
+     LIST = one two three
+     all:
+             for i in $(LIST); do \
+                 echo $$i; \
+             done
+results in the following command being passed to the shell:
+     for i in one two three; do \
+         echo $i; \
+     done
+which generates the expected result:
+     one
+     two
+     three
+File: make.info,  Node: Echoing,  Next: Execution,  Prev: Command Syntax,  Up: Commands
+.2 Command Echoing
+===================
 Normally `make' prints each command line before it is executed.  We
 …
 File: make.info,  Node: Execution,  Next: Parallel,  Prev: Echoing,  Up: Commands
 Command Execution
 =================
+.3 Command Execution
+=====================
 When it is time to execute commands to update a target, they are
+executed by making a new subshell for each line.  (In practice, `make'
+may take shortcuts that do not affect the results.)
+   *Please note:* this implies that shell commands such as `cd' that
+set variables local to each process will not affect the following
+command lines. (1)  If you want to use `cd' to affect the next command,
+put the two on a single line with a semicolon between them.  Then
+`make' will consider them a single command and pass them, together, to
+a shell which will execute them in sequence.  For example:
+executed by invoking a new subshell for each command line.  (In
+practice, `make' may take shortcuts that do not affect the results.)
+   *Please note:* this implies that setting shell variables and
+invoking shell commands such as `cd' that set a context local to each
+process will not affect the following command lines.(1)  If you want to
+use `cd' to affect the next statement, put both statements in a single
+command line.  Then `make' will invoke one shell to run the entire
+line, and the shell will execute the statements in sequence.  For
+example:
      foo : bar/lose
+             cd bar; gobble lose > ../foo
+   If you would like to split a single shell command into multiple
+lines of text, you must use a backslash at the end of all but the last
+subline.  Such a sequence of lines is combined into a single line, by
+deleting the backslash-newline sequences, before passing it to the
+shell.  Thus, the following is equivalent to the preceding example:
+     foo : bar/lose
+             cd bar;  \
+             gobble lose > ../foo
+   The program used as the shell is taken from the variable `SHELL'.
+By default, the program `/bin/sh' is used.
+             cd $(@D) && gobble $(@F) > ../$@
+Here we use the shell AND operator (`&&') so that if the `cd' command
+fails, the script will fail without trying to invoke the `gobble'
+command in the wrong directory, which could cause problems (in this
+case it would certainly cause `../foo' to be truncated, at least).
+* Menu:
+* Choosing the Shell::          How `make' chooses the shell used
+                                  to run commands.
+   ---------- Footnotes ----------
+   (1) On MS-DOS, the value of current working directory is *global*, so
+changing it _will_ affect the following command lines on those systems.
+File: make.info,  Node: Choosing the Shell,  Prev: Execution,  Up: Execution
+.3.1 Choosing the Shell
+------------------------
+The program used as the shell is taken from the variable `SHELL'.  If
+this variable is not set in your makefile, the program `/bin/sh' is
+used as the shell.
+   Unlike most variables, the variable `SHELL' is never set from the
+environment.  This is because the `SHELL' environment variable is used
+to specify your personal choice of shell program for interactive use.
+It would be very bad for personal choices like this to affect the
+functioning of makefiles.  *Note Variables from the Environment:
+Environment.
+   Furthermore, when you do set `SHELL' in your makefile that value is
+_not_ exported in the environment to commands that `make' invokes.
+Instead, the value inherited from the user's environment, if any, is
+exported.  You can override this behavior by explicitly exporting
+`SHELL' (*note Communicating Variables to a Sub-`make':
+Variables/Recursion.), forcing it to be passed in the environment to
+commands.
+   However, on MS-DOS and MS-Windows the value of `SHELL' in the
+environment *is* used, since on those systems most users do not set
+this variable, and therefore it is most likely set specifically to be
+used by `make'.  On MS-DOS, if the setting of `SHELL' is not suitable
+for `make', you can set the variable `MAKESHELL' to the shell that
+`make' should use; if set it will be used as the shell instead of the
+value of `SHELL'.
+Choosing a Shell in DOS and Windows
+...................................
+Choosing a shell in MS-DOS and MS-Windows is much more complex than on
+other systems.
    On MS-DOS, if `SHELL' is not set, the value of the variable
 …
    The effect of the above DOS-specific processing is that a Makefile
+that says `SHELL = /bin/sh' (as many Unix makefiles do), will work on
+MS-DOS unaltered if you have e.g. `sh.exe' installed in some directory
+along your `PATH'.
+   Unlike most variables, the variable `SHELL' is never set from the
+environment.  This is because the `SHELL' environment variable is used
+to specify your personal choice of shell program for interactive use.
+It would be very bad for personal choices like this to affect the
+functioning of makefiles.  *Note Variables from the Environment:
+Environment.  However, on MS-DOS and MS-Windows the value of `SHELL' in
+the environment *is* used, since on those systems most users do not set
+this variable, and therefore it is most likely set specifically to be
+used by `make'.  On MS-DOS, if the setting of `SHELL' is not suitable
+for `make', you can set the variable `MAKESHELL' to the shell that
+`make' should use; this will override the value of `SHELL'.
+   ---------- Footnotes ----------
+   (1) On MS-DOS, the value of current working directory is *global*,
+so changing it _will_ affect the following command lines on those
+systems.
+that contains `SHELL = /bin/sh' (as many Unix makefiles do), will work
+on MS-DOS unaltered if you have e.g. `sh.exe' installed in some
+directory along your `PATH'.
 File: make.info,  Node: Parallel,  Next: Errors,  Prev: Execution,  Up: Commands
 Parallel Execution
 ==================
+.4 Parallel Execution
+======================
 GNU `make' knows how to execute several commands at once.  Normally,
 …
 streams of all but one running command.  This means that attempting to
 read from standard input will usually be a fatal error (a `Broken pipe'
 signal) for most child processes if there are several.
+signal) for most child processes if there are several.
    It is unpredictable which command will have a valid standard input
 …
 File: make.info,  Node: Errors,  Next: Interrupts,  Prev: Parallel,  Up: Commands
 Errors in Commands
 ==================
+.5 Errors in Commands
+======================
 After each shell command returns, `make' looks at its exit status.  If
 …
 program as possible, perhaps to find several independent problems so
 that you can correct them all before the next attempt to compile.  This
 is why Emacs' `compile' command passes the `-k' flag by default.
+is why Emacs' `compile' command passes the `-k' flag by default.
    Usually when a command fails, if it has changed the target file at
 …
 File: make.info,  Node: Interrupts,  Next: Recursion,  Prev: Errors,  Up: Commands
 Interrupting or Killing `make'
 ==============================
+.6 Interrupting or Killing `make'
+==================================
 If `make' gets a fatal signal while a command is executing, it may
 …
 File: make.info,  Node: Recursion,  Next: Sequences,  Prev: Interrupts,  Up: Commands
 Recursive Use of `make'
 =======================
+.7 Recursive Use of `make'
+===========================
 Recursive use of `make' means using `make' as a command in a makefile.
 …
      subsystem:
              $(MAKE) -C subdir
    You can write recursive `make' commands just by copying this example,
 but there are many things to know about how they work and why, and about
 …
 File: make.info,  Node: MAKE Variable,  Next: Variables/Recursion,  Prev: Recursion,  Up: Recursion
 How the `MAKE' Variable Works
 -----------------------------
+.7.1 How the `MAKE' Variable Works
+-----------------------------------
 Recursive `make' commands should always use the variable `MAKE', not
 …
 is `cd subdir && /bin/make'.  If you use a special version of `make' to
 run the top-level makefile, the same special version will be executed
 for recursive invocations.
+for recursive invocations.
    As a special feature, using the variable `MAKE' in the commands of a
 …
 file named `subsystem' and do nothing else.  What you really want it to
 do is run `cd subdir && make -t'; but that would require executing the
 command, and `-t' says not to execute commands.
+command, and `-t' says not to execute commands.
    The special feature makes this do what you want: whenever a command
 …
 File: make.info,  Node: Variables/Recursion,  Next: Options/Recursion,  Prev: MAKE Variable,  Up: Recursion
 Communicating Variables to a Sub-`make'
 ---------------------------------------
+.7.2 Communicating Variables to a Sub-`make'
+---------------------------------------------
 Variable values of the top-level `make' can be passed to the sub-`make'
 …
 characters other than letters, numbers, and underscores.
+   The special variables `SHELL' and `MAKEFLAGS' are always exported
+(unless you unexport them).  `MAKEFILES' is exported if you set it to
+anything.
+   The value of the `make' variable `SHELL' is not exported.  Instead,
+the value of the `SHELL' variable from the invoking environment is
+passed to the sub-`make'.  You can force `make' to export its value for
+`SHELL' by using the `export' directive, described below.  *Note
+Choosing the Shell::.
+   The special variable `MAKEFLAGS' is always exported (unless you
+unexport it).  `MAKEFILES' is exported if you set it to anything.
    `make' automatically passes down variable values that were defined
 …
 `.EXPORT_ALL_VARIABLES' instead of using the `export' directive.  This
 will be ignored by old `make's, while the `export' directive will cause
 a syntax error.
+a syntax error.
    Likewise, you can use `unexport' by itself to tell `make' _not_ to
 …
 File: make.info,  Node: Options/Recursion,  Next: -w Option,  Prev: Variables/Recursion,  Up: Recursion
 Communicating Options to a Sub-`make'
 -------------------------------------
+.7.3 Communicating Options to a Sub-`make'
+-------------------------------------------
 Flags such as `-s' and `-k' are passed automatically to the sub-`make'
 …
 File: make.info,  Node: -w Option,  Prev: Options/Recursion,  Up: Recursion
 The `--print-directory' Option
 ------------------------------
+.7.4 The `--print-directory' Option
+------------------------------------
 If you use several levels of recursive `make' invocations, the `-w' or
 …
 File: make.info,  Node: Sequences,  Next: Empty Commands,  Prev: Recursion,  Up: Commands
 Defining Canned Command Sequences
 =================================
+.8 Defining Canned Command Sequences
+=====================================
 When the same sequence of commands is useful in making various targets,
 …
      mv y.tab.c $@
      endef
 Here `run-yacc' is the name of the variable being defined; `endef'
 marks the end of the definition; the lines in between are the commands.
 …
 File: make.info,  Node: Empty Commands,  Prev: Sequences,  Up: Commands
 Using Empty Commands
 ====================
+.9 Using Empty Commands
+========================
 It is sometimes useful to define commands which do nothing.  This is
 …
 File: make.info,  Node: Using Variables,  Next: Conditionals,  Prev: Commands,  Up: Top
 How to Use Variables
 ********************
+How to Use Variables
+**********************
 A "variable" is a name defined in a makefile to represent a string of
 …
 explicit request into targets, prerequisites, commands, and other parts
 of the makefile.  (In some other versions of `make', variables are
 called "macros".)
+called "macros".)
    Variables and functions in all parts of a makefile are expanded when
 …
 File: make.info,  Node: Reference,  Next: Flavors,  Prev: Using Variables,  Up: Using Variables
 Basics of Variable References
 =============================
+.1 Basics of Variable References
+=================================
 To substitute a variable's value, write a dollar sign followed by the
 …
      program : $(objects)
              cc -o program $(objects)
      $(objects) : defs.h
 …
 File: make.info,  Node: Flavors,  Next: Advanced,  Prev: Reference,  Up: Using Variables
 The Two Flavors of Variables
 ============================
+.2 The Two Flavors of Variables
+================================
 There are two ways that a variable in GNU `make' can have a value; we
 …
      bar = $(ugh)
      ugh = Huh?
      all:;echo $(foo)
 …
 because it will cause an infinite loop in the variable expansion.
 (Actually `make' detects the infinite loop and reports an error.)
+(Actually `make' detects the infinite loop and reports an error.)
    Another disadvantage is that any functions (*note Functions for
 …
      ifeq (0,${MAKELEVEL})
-     cur-dir   := $(shell pwd)
      whoami    := $(shell whoami)
      host-type := $(shell arch)
 …
      ${subdirs}:
            ${MAKE} cur-dir=${cur-dir}/$@ -C $@ all
+             ${MAKE} -C $@ all
    Simply expanded variables generally make complicated makefile
 …
 File: make.info,  Node: Advanced,  Next: Values,  Prev: Flavors,  Up: Using Variables
 Advanced Features for Reference to Variables
 ============================================
+.3 Advanced Features for Reference to Variables
+================================================
 This section describes some advanced features you can use to reference
 …
 File: make.info,  Node: Substitution Refs,  Next: Computed Names,  Prev: Advanced,  Up: Advanced
 Substitution References
 -----------------------
+.3.1 Substitution References
+-----------------------------
 A "substitution reference" substitutes the value of a variable with
 …
 For example:
      foo := a.o b.o c.o
      bar := $(foo:%.o=%.c)
 …
 File: make.info,  Node: Computed Names,  Prev: Substitution Refs,  Up: Advanced
 Computed Variable Names
 -----------------------
+.3.2 Computed Variable Names
+-----------------------------
 Computed variable names are a complicated concept needed only for
 …
      a_dirs := dira dirb
 _dirs := dir1 dir2
      a_files := filea fileb
 _files := file1 file2
      ifeq "$(use_a)" "yes"
      a1 := a
 …
      a1 := 1
      endif
      ifeq "$(use_dirs)" "yes"
      df := dirs
 …
      df := files
      endif
      dirs := $($(a1)_$(df))
 …
      a_objects := a.o b.o c.o
 _objects := 1.o 2.o 3.o
      sources := $($(a1)_objects:.o=.c)
 …
      func := strip
      endif
      bar := a d b g q c
      foo := $($(func) $(bar))
 …
 File: make.info,  Node: Values,  Next: Setting,  Prev: Advanced,  Up: Using Variables
 How Variables Get Their Values
 ==============================
+.4 How Variables Get Their Values
+==================================
 Variables can get values in several different ways:
 …
 File: make.info,  Node: Setting,  Next: Appending,  Prev: Values,  Up: Using Variables
 Setting Variables
 =================
+.5 Setting Variables
+=====================
 To set a variable from the makefile, write a line starting with the
 …
 File: make.info,  Node: Appending,  Next: Override Directive,  Prev: Setting,  Up: Using Variables
 Appending More Text to Variables
 ================================
+.6 Appending More Text to Variables
+====================================
 Often it is useful to add more text to the value of a variable already
 …
 it a simply-expanded variable, `+=' adds to that simply-expanded
 definition, and expands the new text before appending it to the old
 value just as `:=' does (*note Setting Variables: Setting., for a full
 explanation of `:=').  In fact,
+value just as `:=' does (see *Note Setting Variables: Setting, for a
+full explanation of `:=').  In fact,
      variable := value
 …
 is exactly equivalent to:
      variable := value
 …
 The first line defines the `CFLAGS' variable with a reference to another
 variable, `includes'.  (`CFLAGS' is used by the rules for C
 compilation; *note Catalogue of Implicit Rules: Catalogue of Rules..)
+compilation; *note Catalogue of Implicit Rules: Catalogue of Rules.)
 Using `=' for the definition makes `CFLAGS' a recursively-expanded
 variable, meaning `$(includes) -O' is _not_ expanded when `make'
 …
 File: make.info,  Node: Override Directive,  Next: Defining,  Prev: Appending,  Up: Using Variables
 The `override' Directive
 ========================
+.7 The `override' Directive
+============================
 If a variable has been set with a command argument (*note Overriding
 …
 File: make.info,  Node: Defining,  Next: Environment,  Prev: Override Directive,  Up: Using Variables
 Defining Variables Verbatim
 ===========================
+.8 Defining Variables Verbatim
+===============================
 Another way to set the value of a variable is to use the `define'
 …
 File: make.info,  Node: Environment,  Next: Target-specific,  Prev: Defining,  Up: Using Variables
 Variables from the Environment
 ==============================
+.9 Variables from the Environment
+==================================
 Variables in `make' can come from the environment in which `make' is
 run.  Every environment variable that `make' sees when it starts up is
 transformed into a `make' variable with the same name and value.  But
+an explicit assignment in the makefile, or with a command argument,
+overrides the environment.  (If the `-e' flag is specified, then values
+from the environment override assignments in the makefile.  *Note
 Summary of Options: Options Summary.  But this is not recommended
+transformed into a `make' variable with the same name and value.
+However, an explicit assignment in the makefile, or with a command
+argument, overrides the environment.  (If the `-e' flag is specified,
+then values from the environment override assignments in the makefile.
+*Note Summary of Options: Options Summary.  But this is not recommended
 practice.)
 …
 you prefer.  This is safe for variables with standard or conventional
 meanings because you know that no makefile will use them for other
 things.  (But this is not totally reliable; some makefiles set `CFLAGS'
 explicitly and therefore are not affected by the value in the
+things.  (Note this is not totally reliable; some makefiles set
+`CFLAGS' explicitly and therefore are not affected by the value in the
 environment.)
    When `make' is invoked recursively, variables defined in the outer
+invocation can be passed to inner invocations through the environment
+(*note Recursive Use of `make': Recursion.).  By default, only
+variables that came from the environment or the command line are passed
+to recursive invocations.  You can use the `export' directive to pass
+other variables.  *Note Communicating Variables to a Sub-`make':
 Variables/Recursion, for full details.
+   When `make' runs a command script, variables defined in the makefile
+are placed into the environment of that command.  This allows you to
+pass values to sub-`make' invocations (*note Recursive Use of `make':
+Recursion.).  By default, only variables that came from the environment
+or the command line are passed to recursive invocations.  You can use
+the `export' directive to pass other variables.  *Note Communicating
+Variables to a Sub-`make': Variables/Recursion, for full details.
    Other use of variables from the environment is not recommended.  It
 …
 which is normally present in the environment to specify the user's
 choice of interactive shell.  It would be very undesirable for this
+choice to affect `make'.  So `make' ignores the environment value of
+`SHELL' (except on MS-DOS and MS-Windows, where `SHELL' is usually not
+set.  *Note Special handling of SHELL on MS-DOS: Execution.)
+choice to affect `make'; so, `make' handles the `SHELL' environment
+variable in a special way; see *Note Choosing the Shell::.
 File: make.info,  Node: Target-specific,  Next: Pattern-specific,  Prev: Environment,  Up: Using Variables
 Target-specific Variable Values
 ===============================
+.10 Target-specific Variable Values
+====================================
 Variable values in `make' are usually global; that is, they are the
 …
 File: make.info,  Node: Pattern-specific,  Prev: Target-specific,  Up: Using Variables
 Pattern-specific Variable Values
 ================================
+.11 Pattern-specific Variable Values
+=====================================
 In addition to target-specific variable values (*note Target-specific
 …
 File: make.info,  Node: Conditionals,  Next: Functions,  Prev: Using Variables,  Up: Top
 Conditional Parts of Makefiles
 ******************************
+Conditional Parts of Makefiles
+********************************
 A "conditional" causes part of a makefile to be obeyed or ignored
 …
 File: make.info,  Node: Conditional Example,  Next: Conditional Syntax,  Prev: Conditionals,  Up: Conditionals
 Example of a Conditional
 ========================
+.1 Example of a Conditional
+============================
 The following example of a conditional tells `make' to use one set of
 …
      libs_for_gcc = -lgnu
      normal_libs =
      foo: $(objects)
      ifeq ($(CC),gcc)
 …
      libs_for_gcc = -lgnu
      normal_libs =
      ifeq ($(CC),gcc)
        libs=$(libs_for_gcc)
 …
        libs=$(normal_libs)
      endif
      foo: $(objects)
              $(CC) -o foo $(objects) $(libs)
 …
 File: make.info,  Node: Conditional Syntax,  Next: Testing Flags,  Prev: Conditional Example,  Up: Conditionals
 Syntax of Conditionals
 ======================
+.2 Syntax of Conditionals
+==========================
 The syntax of a simple conditional with no `else' is as follows:
 …
      endif
+If the condition is true, TEXT-IF-TRUE is used; otherwise,
+TEXT-IF-FALSE is used instead.  The TEXT-IF-FALSE can be any number of
+lines of text.
+   or:
+     CONDITIONAL-DIRECTIVE
+     TEXT-IF-ONE-IS-TRUE
+     else CONDITIONAL-DIRECTIVE
+     TEXT-IF-TRUE
+     else
+     TEXT-IF-FALSE
+     endif
+There can be as many "`else' CONDITIONAL-DIRECTIVE" clauses as
+necessary.  Once a given condition is true, TEXT-IF-TRUE is used and no
+other clause is used; if no condition is true then TEXT-IF-FALSE is
+used.  The TEXT-IF-TRUE and TEXT-IF-FALSE can be any number of lines of
+text.
    The syntax of the CONDITIONAL-DIRECTIVE is the same whether the
+conditional is simple or complex.  There are four different directives
+that test different conditions.  Here is a table of them:
+conditional is simple or complex; after an `else' or not.  There are
+four different directives that test different conditions.  Here is a
+table of them:
 `ifeq (ARG1, ARG2)'
 …
 `ifdef VARIABLE-NAME'
+     If the variable VARIABLE-NAME has a non-empty value, the
+     TEXT-IF-TRUE is effective; otherwise, the TEXT-IF-FALSE, if any,
+     is effective.  Variables that have never been defined have an
+     empty value.  The variable VARIABLE-NAME is itself expanded, so it
+     could be a variable or function that expands to the name of a
+     variable.
+     The `ifdef' form takes the _name_ of a variable as its argument,
+     not a reference to a variable.  The value of that variable has a
+     non-empty value, the TEXT-IF-TRUE is effective; otherwise, the
+     TEXT-IF-FALSE, if any, is effective.  Variables that have never
+     been defined have an empty value.  The text VARIABLE-NAME is
+     expanded, so it could be a variable or function that expands to
+     the name of a variable.  For example:
+          bar = true
+          foo = bar
+          ifdef $(foo)
+          frobozz = yes
+          endif
+     The variable reference `$(foo)' is expanded, yielding `bar', which
+     is considered to be the name of a variable.  The variable `bar' is
+     not expanded, but its value is examined to determine if it is
+     non-empty.
      Note that `ifdef' only tests whether a variable has a value.  It
 …
      If the variable VARIABLE-NAME has an empty value, the TEXT-IF-TRUE
      is effective; otherwise, the TEXT-IF-FALSE, if any, is effective.
+     The rules for expansion and testing of VARIABLE-NAME are identical
+     to the `ifdef' directive.
    Extra spaces are allowed and ignored at the beginning of the
 …
 File: make.info,  Node: Testing Flags,  Prev: Conditional Syntax,  Up: Conditionals
 Conditionals that Test Flags
 ============================
+.3 Conditionals that Test Flags
+================================
 You can write a conditional that tests `make' command flags such as
 …
 File: make.info,  Node: Functions,  Next: Running,  Prev: Conditionals,  Up: Top
 Functions for Transforming Text
 *******************************
+Functions for Transforming Text
+*********************************
 "Functions" allow you to do text processing in the makefile to compute
 …
 * Text Functions::              General-purpose text manipulation functions.
 * File Name Functions::         Functions for manipulating file names.
+* Conditional Functions::       Functions that implement conditions.
 * Foreach Function::            Repeat some text with controlled variation.
-* If Function::                 Conditionally expand a value.
 * Call Function::               Expand a user-defined function.
 * Value Function::              Return the un-expanded value of a variable.
 * Eval Function::               Evaluate the arguments as makefile syntax.
 * Origin Function::             Find where a variable got its value.
+* Flavor Function::             Find out the flavor of a variable.
 * Shell Function::              Substitute the output of a shell command.
 * Make Control Functions::      Functions that control how make runs.
 …
 File: make.info,  Node: Syntax of Functions,  Next: Text Functions,  Prev: Functions,  Up: Functions
 Function Call Syntax
 ====================
+.1 Function Call Syntax
+========================
 A function call resembles a variable reference.  It looks like this:
 …
 File: make.info,  Node: Text Functions,  Next: File Name Functions,  Prev: Syntax of Functions,  Up: Functions
 Functions for String Substitution and Analysis
 ==============================================
+.2 Functions for String Substitution and Analysis
+==================================================
 Here are some functions that operate on strings:
 …
 `$(wordlist S,E,TEXT)'
      Returns the list of words in TEXT starting with word S and ending
      with word E (inclusive).  The legitimate values of S and E start
      from 1.  If S is bigger than the number of words in TEXT, the
      value is empty.  If E is bigger than the number of words in TEXT,
      words up to the end of TEXT are returned.  If S is greater than E,
      nothing is returned.  For example,
+     with word E (inclusive).  The legitimate values of S start from 1;
+     E may start from 0.  If S is bigger than the number of words in
+     TEXT, the value is empty.  If E is bigger than the number of words
+     in TEXT, words up to the end of TEXT are returned.  If S is
+     greater than E, nothing is returned.  For example,
           $(wordlist 2, 3, foo bar baz)
 …
      same as `$(word 1,TEXT)', the `firstword' function is retained for
      its simplicity.
+`$(lastword NAMES...)'
+     The argument NAMES is regarded as a series of names, separated by
+     whitespace.  The value is the last name in the series.
+     For example,
+          $(lastword foo bar)
+     produces the result `bar'.  Although `$(lastword TEXT)' is the
+     same as `$(word $(words TEXT),TEXT)', the `lastword' function was
+     added for its simplicity and better performance.
    Here is a realistic example of the use of `subst' and `patsubst'.
 …
 File: make.info,  Node: File Name Functions,  Next: Foreach Function,  Prev: Text Functions,  Up: Functions
 Functions for File Names
 ========================
+File: make.info,  Node: File Name Functions,  Next: Conditional Functions,  Prev: Text Functions,  Up: Functions
+.3 Functions for File Names
+============================
 Several of the built-in expansion functions relate specifically to
 …
      File Names: Wildcards.
+File: make.info,  Node: Foreach Function,  Next: If Function,  Prev: File Name Functions,  Up: Functions
+The `foreach' Function
+======================
+`$(realpath NAMES...)'
+     For each file name in NAMES return the canonical absolute name.  A
+     canonical name does not contain any `.' or `..' components, nor
+     any repeated path separators (`/') or symlinks.  In case of a
+     failure the empty string is returned.  Consult the `realpath(3)'
+     documentation for a list of possible failure causes.
+`$(abspath NAMES...)'
+     For each file name in NAMES return an absolute name that does not
+     contain any `.' or `..' components, nor any repeated path
+     separators (`/').  Note that, in contrast to `realpath' function,
+     `abspath' does not resolve symlinks and does not require the file
+     names to refer to an existing file or directory.  Use the
+     `wildcard' function to test for existence.
+File: make.info,  Node: Conditional Functions,  Next: Foreach Function,  Prev: File Name Functions,  Up: Functions
+.4 Functions for Conditionals
+==============================
+There are three functions that provide conditional expansion.  A key
+aspect of these functions is that not all of the arguments are expanded
+initially.  Only those arguments which need to be expanded, will be
+expanded.
+`$(if CONDITION,THEN-PART[,ELSE-PART])'
+     The `if' function provides support for conditional expansion in a
+     functional context (as opposed to the GNU `make' makefile
+     conditionals such as `ifeq' (*note Syntax of Conditionals:
+     Conditional Syntax.).
+     The first argument, CONDITION, first has all preceding and
+     trailing whitespace stripped, then is expanded.  If it expands to
+     any non-empty string, then the condition is considered to be true.
+     If it expands to an empty string, the condition is considered to
+     be false.
+     If the condition is true then the second argument, THEN-PART, is
+     evaluated and this is used as the result of the evaluation of the
+     entire `if' function.
+     If the condition is false then the third argument, ELSE-PART, is
+     evaluated and this is the result of the `if' function.  If there is
+     no third argument, the `if' function evaluates to nothing (the
+     empty string).
+     Note that only one of the THEN-PART or the ELSE-PART will be
+     evaluated, never both.  Thus, either can contain side-effects
+     (such as `shell' function calls, etc.)
+`$(or CONDITION1[,CONDITION2[,CONDITION3...]])'
+     The `or' function provides a "short-circuiting" OR operation.
+     Each argument is expanded, in order.  If an argument expands to a
+     non-empty string the processing stops and the result of the
+     expansion is that string.  If, after all arguments are expanded,
+     all of them are false (empty), then the result of the expansion is
+     the empty string.
+`$(and CONDITION1[,CONDITION2[,CONDITION3...]])'
+     The `and' function provides a "short-circuiting" AND operation.
+     Each argument is expanded, in order.  If an argument expands to an
+     empty string the processing stops and the result of the expansion
+     is the empty string.  If all arguments expand to a non-empty
+     string then the result of the expansion is the expansion of the
+     last argument.
+File: make.info,  Node: Foreach Function,  Next: Call Function,  Prev: Conditional Functions,  Up: Functions
+.5 The `foreach' Function
+==========================
 The `foreach' function is very different from other functions.  It
 …
+File: make.info,  Node: If Function,  Next: Call Function,  Prev: Foreach Function,  Up: Functions
+The `if' Function
+=================
+The `if' function provides support for conditional expansion in a
+functional context (as opposed to the GNU `make' makefile conditionals
+such as `ifeq' (*note Syntax of Conditionals: Conditional Syntax.).
+   An `if' function call can contain either two or three arguments:
+     $(if CONDITION,THEN-PART[,ELSE-PART])
+   The first argument, CONDITION, first has all preceding and trailing
+whitespace stripped, then is expanded.  If it expands to any non-empty
+string, then the condition is considered to be true.  If it expands to
+an empty string, the condition is considered to be false.
+   If the condition is true then the second argument, THEN-PART, is
+evaluated and this is used as the result of the evaluation of the entire
+`if' function.
+   If the condition is false then the third argument, ELSE-PART, is
+evaluated and this is the result of the `if' function.  If there is no
+third argument, the `if' function evaluates to nothing (the empty
+string).
+   Note that only one of the THEN-PART or the ELSE-PART will be
+evaluated, never both.  Thus, either can contain side-effects (such as
+`shell' function calls, etc.)
+File: make.info,  Node: Call Function,  Next: Value Function,  Prev: If Function,  Up: Functions
+The `call' Function
+===================
+File: make.info,  Node: Call Function,  Next: Value Function,  Prev: Foreach Function,  Up: Functions
+.6 The `call' Function
+=======================
 The `call' function is unique in that it can be used to create new
 …
      reverse = $(2) $(1)
      foo = $(call reverse,a,b)
 …
      pathsearch = $(firstword $(wildcard $(addsuffix /$(1),$(subst :, ,$(PATH)))))
      LS := $(call pathsearch,ls)
 …
 File: make.info,  Node: Value Function,  Next: Eval Function,  Prev: Call Function,  Up: Functions
 The `value' Function
 ====================
+.7 The `value' Function
+========================
 The `value' function provides a way for you to use the value of a
 …
      FOO = $PATH
      all:
              @echo $(FOO)
 …
 File: make.info,  Node: Eval Function,  Next: Origin Function,  Prev: Value Function,  Up: Functions
 The `eval' Function
 ===================
+.8 The `eval' Function
+=======================
 The `eval' function is very special: it allows you to define new
 …
      PROGRAMS    = server client
      server_OBJS = server.o server_priv.o server_access.o
      server_LIBS = priv protocol
      client_OBJS = client.o client_api.o client_mem.o
      client_LIBS = protocol
      # Everything after this is generic
      .PHONY: all
      all: $(PROGRAMS)
      define PROGRAM_template
       $(1): $$($(1)_OBJS) $$($(1)_LIBS:%=-l%)
       ALL_OBJS   += $$($(1)_OBJS)
      endef
      $(foreach prog,$(PROGRAMS),$(eval $(call PROGRAM_template,$(prog))))
      $(PROGRAMS):
              $(LINK.o) $^ $(LDLIBS) -o $@
      clean:
              rm -f $(ALL_OBJS) $(PROGRAMS)
 File: make.info,  Node: Origin Function,  Next: Shell Function,  Prev: Eval Function,  Up: Functions
 The `origin' Function
 =====================
+File: make.info,  Node: Origin Function,  Next: Flavor Function,  Prev: Eval Function,  Up: Functions
+.9 The `origin' Function
+=========================
 The `origin' function is unlike most other functions in that it does
 …
+File: make.info,  Node: Shell Function,  Next: Make Control Functions,  Prev: Origin Function,  Up: Functions
+The `shell' Function
+====================
+File: make.info,  Node: Flavor Function,  Next: Shell Function,  Prev: Origin Function,  Up: Functions
+.10 The `flavor' Function
+==========================
+The `flavor' function is unlike most other functions (and like `origin'
+function) in that it does not operate on the values of variables; it
+tells you something _about_ a variable.  Specifically, it tells you the
+flavor of a variable (*note The Two Flavors of Variables: Flavors.).
+   The syntax of the `flavor' function is:
+     $(flavor VARIABLE)
+   Note that VARIABLE is the _name_ of a variable to inquire about; not
+a _reference_ to that variable.  Therefore you would not normally use a
+`$' or parentheses when writing it.  (You can, however, use a variable
+reference in the name if you want the name not to be a constant.)
+   The result of this function is a string that identifies the flavor
+of the variable VARIABLE:
+`undefined'
+     if VARIABLE was never defined.
+`recursive'
+     if VARIABLE is a recursively expanded variable.
+`simple'
+     if VARIABLE is a simply expanded variable.
+File: make.info,  Node: Shell Function,  Next: Make Control Functions,  Prev: Flavor Function,  Up: Functions
+.11 The `shell' Function
+=========================
 The `shell' function is unlike any other function other than the
 …
 sets `files' to the expansion of `*.c'.  Unless `make' is using a very
+strange shell, this has the same result as `$(wildcard *.c)'.
+strange shell, this has the same result as `$(wildcard *.c)' (as long
+as at least one `.c' file exists).
 File: make.info,  Node: Make Control Functions,  Prev: Shell Function,  Up: Functions
 Functions That Control Make
 ===========================
+.12 Functions That Control Make
+================================
 These functions control the way make runs.  Generally, they are used to
 …
           ERR = $(error found an error!)
           .PHONY: err
           err: ; $(ERR)
 …
      The result of the expansion of this function is the empty string.
+`$(info TEXT...)'
+     This function does nothing more than print its (expanded)
+     argument(s) to standard output.  No makefile name or line number
+     is added.  The result of the expansion of this function is the
+     empty string.
 File: make.info,  Node: Running,  Next: Implicit Rules,  Prev: Functions,  Up: Top
 How to Run `make'
 *****************
+How to Run `make'
+*******************
 A makefile that says how to recompile a program can be used in more
 …
 File: make.info,  Node: Makefile Arguments,  Next: Goals,  Prev: Running,  Up: Running
 Arguments to Specify the Makefile
 =================================
+.1 Arguments to Specify the Makefile
+=====================================
 The way to specify the name of the makefile is with the `-f' or
 …
 File: make.info,  Node: Goals,  Next: Instead of Execution,  Prev: Makefile Arguments,  Up: Running
 Arguments to Specify the Goals
 ==============================
+.2 Arguments to Specify the Goals
+==================================
 The "goals" are the targets that `make' should strive ultimately to
 …
 program or programs they describe.  If the first rule in the makefile
 has several targets, only the first target in the rule becomes the
+default goal, not the whole list.
+   You can specify a different goal or goals with arguments to `make'.
+Use the name of the goal as an argument.  If you specify several goals,
+`make' processes each of them in turn, in the order you name them.
+default goal, not the whole list.  You can manage the selection of the
+default goal from within your makefile using the `.DEFAULT_GOAL'
+variable (*note Other Special Variables: Special Variables.).
+   You can also specify a different goal or goals with command-line
+arguments to `make'.  Use the name of the goal as an argument.  If you
+specify several goals, `make' processes each of them in turn, in the
+order you name them.
    Any target in the makefile may be specified as a goal (unless it
 …
      sources = foo.c bar.c
      ifneq ($(MAKECMDGOALS),clean)
      include $(sources:.c=.d)
 …
 File: make.info,  Node: Instead of Execution,  Next: Avoiding Compilation,  Prev: Goals,  Up: Running
 Instead of Executing the Commands
 =================================
+.3 Instead of Executing the Commands
+=====================================
 The makefile tells `make' how to tell whether a target is up to date,
 …
 File: make.info,  Node: Avoiding Compilation,  Next: Overriding,  Prev: Instead of Execution,  Up: Running
 Avoiding Recompilation of Some Files
 ====================================
+.4 Avoiding Recompilation of Some Files
+========================================
 Sometimes you may have changed a source file but you do not want to
 …
 File: make.info,  Node: Overriding,  Next: Testing,  Prev: Avoiding Compilation,  Up: Running
 Overriding Variables
 ====================
+.5 Overriding Variables
+========================
 An argument that contains `=' specifies the value of a variable: `V=X'
 …
 File: make.info,  Node: Testing,  Next: Options Summary,  Prev: Overriding,  Up: Running
 Testing the Compilation of a Program
 ====================================
+.6 Testing the Compilation of a Program
+========================================
 Normally, when an error happens in executing a shell command, `make'
 …
 File: make.info,  Node: Options Summary,  Prev: Testing,  Up: Running
 Summary of Options
 ==================
+.7 Summary of Options
+======================
 Here is a table of all the options `make' understands:
 …
      Consider all targets out-of-date.  GNU `make' proceeds to consider
      targets and their prerequisites using the normal algorithms;
+     however, all these targets are remade, regardless of the status of
+     their prerequisites.
+     however, all targets so considered are always remade regardless of
+     the status of their prerequisites.  To avoid infinite recursion, if
+     `MAKE_RESTARTS' (*note Other Special Variables: Special
+     Variables.) is set to a number greater than 0 this option is
+     disabled when considering whether to remake makefiles (*note How
+     Makefiles Are Remade: Remaking Makefiles.).
 `-C DIR'
 …
      floating-point number).  With no argument, removes a previous load
      limit.  *Note Parallel Execution: Parallel.
+`-L'
+`--check-symlink-times'
+     On systems that support symbolic links, this option causes `make'
+     to consider the timestamps on any symbolic links in addition to the
+     timestamp on the file referenced by those links.  When this option
+     is provided, the most recent timestamp among the file and the
+     symbolic links is taken as the modification time for this target
+     file.
 `-n'
 …
 File: make.info,  Node: Implicit Rules,  Next: Archives,  Prev: Running,  Up: Top
 Using Implicit Rules
 ********************
+Using Implicit Rules
+***********************
 Certain standard ways of remaking target files are used very often.  For
 …
 * Chained Rules::               How to use a chain of implicit rules.
 * Pattern Rules::               How to define new implicit rules.
 * Last Resort::                 How to defining commands for rules
                                   which cannot find any.
+* Last Resort::                 How to define commands for rules which
+                                  cannot find any.
 * Suffix Rules::                The old-fashioned style of implicit rule.
 * Implicit Rule Search::        The precise algorithm for applying
 …
 File: make.info,  Node: Using Implicit,  Next: Catalogue of Rules,  Prev: Implicit Rules,  Up: Implicit Rules
 Using Implicit Rules
 ====================
+.1 Using Implicit Rules
+=========================
 To allow `make' to find a customary method for updating a target file,
 …
 File: make.info,  Node: Catalogue of Rules,  Next: Implicit Variables,  Prev: Using Implicit,  Up: Implicit Rules
 Catalogue of Implicit Rules
 ===========================
+.2 Catalogue of Implicit Rules
+================================
 Here is a catalogue of predefined implicit rules which are always
 …
 `--no-builtin-rules' option cancels all predefined rules.
+   This manual only documents the default rules available on POSIX-based
+operating systems.  Other operating systems, such as VMS, Windows,
+OS/2, etc. may have different sets of default rules.  To see the full
+list of default rules and variables available in your version of GNU
+`make', run `make -p' in a directory with no makefile.
    Not all of these rules will always be defined, even when the `-r'
 option is not given.  Many of the predefined implicit rules are
 …
 depends on the "suffix list" (the list of prerequisites of the special
 target `.SUFFIXES').  The default suffix list is: `.out', `.a', `.ln',
 `.o', `.c', `.cc', `.C', `.p', `.f', `.F', `.r', `.y', `.l', `.s',
 `.S', `.mod', `.sym', `.def', `.h', `.info', `.dvi', `.tex', `.texinfo',
 `.texi', `.txinfo', `.w', `.ch' `.web', `.sh', `.elc', `.el'.  All of
+the implicit rules described below whose prerequisites have one of
+these suffixes are actually suffix rules.  If you modify the suffix
+list, the only predefined suffix rules in effect will be those named by
+one or two of the suffixes that are on the list you specify; rules
+whose suffixes fail to be on the list are disabled.  *Note
+Old-Fashioned Suffix Rules: Suffix Rules, for full details on suffix
 rules.
+`.o', `.c', `.cc', `.C', `.cpp', `.p', `.f', `.F', `.r', `.y', `.l',
+`.s', `.S', `.mod', `.sym', `.def', `.h', `.info', `.dvi', `.tex',
+`.texinfo', `.texi', `.txinfo', `.w', `.ch' `.web', `.sh', `.elc',
+`.el'.  All of the implicit rules described below whose prerequisites
+have one of these suffixes are actually suffix rules.  If you modify
+the suffix list, the only predefined suffix rules in effect will be
+those named by one or two of the suffixes that are on the list you
+specify; rules whose suffixes fail to be on the list are disabled.
+*Note Old-Fashioned Suffix Rules: Suffix Rules, for full details on
+suffix rules.
 Compiling C programs
 …
 Compiling C++ programs
+     `N.o' is made automatically from `N.cc' or `N.C' with a command of
+     the form `$(CXX) -c $(CPPFLAGS) $(CXXFLAGS)'.  We encourage you to
+     use the suffix `.cc' for C++ source files instead of `.C'.
+     `N.o' is made automatically from `N.cc', `N.cpp', or `N.C' with a
+     command of the form `$(CXX) -c $(CPPFLAGS) $(CXXFLAGS)'.  We
+     encourage you to use the suffix `.cc' for C++ source files instead
+     of `.C'.
 Compiling Pascal programs
 …
 File: make.info,  Node: Implicit Variables,  Next: Chained Rules,  Prev: Catalogue of Rules,  Up: Implicit Rules
 Variables Used by Implicit Rules
 ================================
+.3 Variables Used by Implicit Rules
+=====================================
 The commands in built-in implicit rules make liberal use of certain
 predefined variables.  You can alter these variables in the makefile,
+with arguments to `make', or in the environment to alter how the
+implicit rules work without redefining the rules themselves.  You can
 cancel all variables used by implicit rules with the `-R' or
+predefined variables.  You can alter the values of these variables in
+the makefile, with arguments to `make', or in the environment to alter
+how the implicit rules work without redefining the rules themselves.
+You can cancel all variables used by implicit rules with the `-R' or
 `--no-builtin-variables' option.
 …
 argument, separate them with spaces.
+   Here is a table of variables used as names of programs in built-in
+rules:
+   The following tables describe of some of the more commonly-used
+predefined variables.  This list is not exhaustive, and the default
+values shown here may not be what are selected by `make' for your
+environment.  To see the complete list of predefined variables for your
+instance of GNU `make' you can run `make -p' in a directory with no
+makefiles.
+   Here is a table of some of the more common variables used as names of
+programs in built-in rules: makefiles.
 `AR'
      Archive-maintaining program; default `ar'.
+     Archive-maintaining program; default `ar'.
 `AS'
      Program for doing assembly; default `as'.
+     Program for compiling assembly files; default `as'.
 `CC'
+     Program for compiling C programs; default `cc'.
+     Program for compiling C programs; default `cc'.
+`CO'
+     Program for checking out files from RCS; default `co'.
 `CXX'
      Program for compiling C++ programs; default `g++'.
+     Program for compiling C++ programs; default `g++'.
 `CO'
      Program for extracting a file from RCS; default `co'.
+     Program for extracting a file from RCS; default `co'.
 `CPP'
 …
 `FC'
      Program for compiling or preprocessing Fortran and Ratfor programs;
      default `f77'.
+     default `f77'.
 `GET'
      Program for extracting a file from SCCS; default `get'.
+     Program for extracting a file from SCCS; default `get'.
 `LEX'
+     Program to use to turn Lex grammars into C programs or Ratfor
+     programs; default `lex'.
+     Program to use to turn Lex grammars into source code; default
+     `lex'.
+`YACC'
+     Program to use to turn Yacc grammars into source code; default
+     `yacc'.
+`LINT'
+     Program to use to run lint on source code; default `lint'.
+`M2C'
+     Program to use to compile Modula-2 source code; default `m2c'.
 `PC'
+     Program for compiling Pascal programs; default `pc'.
+`YACC'
+     Program to use to turn Yacc grammars into C programs; default
+     `yacc'.
+`YACCR'
+     Program to use to turn Yacc grammars into Ratfor programs; default
+     `yacc -r'.
+     Program for compiling Pascal programs; default `pc'.
 `MAKEINFO'
      Program to convert a Texinfo source file into an Info file; default
      `makeinfo'.
+     `makeinfo'.
 `TEX'
      Program to make TeX DVI files from TeX source; default `tex'.
+     Program to make TeX DVI files from TeX source; default `tex'.
 `TEXI2DVI'
      Program to make TeX DVI files from Texinfo source; default
      `texi2dvi'.
+     `texi2dvi'.
 `WEAVE'
      Program to translate Web into TeX; default `weave'.
+     Program to translate Web into TeX; default `weave'.
 `CWEAVE'
      Program to translate C Web into TeX; default `cweave'.
+     Program to translate C Web into TeX; default `cweave'.
 `TANGLE'
      Program to translate Web into Pascal; default `tangle'.
+     Program to translate Web into Pascal; default `tangle'.
 `CTANGLE'
      Program to translate C Web into C; default `ctangle'.
+     Program to translate C Web into C; default `ctangle'.
 `RM'
      Command to remove a file; default `rm -f'.
+     Command to remove a file; default `rm -f'.
    Here is a table of variables whose values are additional arguments
 …
      Extra flags to give to Lex.
+`YFLAGS'
+     Extra flags to give to Yacc.
 `PFLAGS'
      Extra flags to give to the Pascal compiler.
 …
      Extra flags to give to the Fortran compiler for Ratfor programs.
 `YFLAGS'
      Extra flags to give to Yacc.
+`LINTFLAGS'
+     Extra flags to give to lint.
 File: make.info,  Node: Chained Rules,  Next: Pattern Rules,  Prev: Implicit Variables,  Up: Implicit Rules
 Chains of Implicit Rules
 ========================
+.4 Chains of Implicit Rules
+=============================
 Sometimes a file can be made by a sequence of implicit rules.  For
 …
 as a prerequisite of the special target `.PRECIOUS' to preserve
 intermediate files made by implicit rules whose target patterns match
 that file's name; see *Note Interrupts::.
+that file's name; see *Note Interrupts::.
    A chain can involve more than two implicit rules.  For example, it is
 …
 earlier in the ordering of rules.
-File: make.info,  Node: Pattern Rules,  Next: Last Resort,  Prev: Chained Rules,  Up: Implicit Rules
-Defining and Redefining Pattern Rules
-=====================================
-You define an implicit rule by writing a "pattern rule".  A pattern
-rule looks like an ordinary rule, except that its target contains the
-character `%' (exactly one of them).  The target is considered a
-pattern for matching file names; the `%' can match any nonempty
-substring, while other characters match only themselves.  The
-prerequisites likewise use `%' to show how their names relate to the
-target name.
-   Thus, a pattern rule `%.o : %.c' says how to make any file `STEM.o'
-from another file `STEM.c'.
-   Note that expansion using `%' in pattern rules occurs *after* any
-variable or function expansions, which take place when the makefile is
-read.  *Note How to Use Variables: Using Variables, and *Note Functions
-for Transforming Text: Functions.
-* Menu:
-* Pattern Intro::               An introduction to pattern rules.
-* Pattern Examples::            Examples of pattern rules.
-* Automatic Variables::         How to use automatic variables in the
-                                  commands of implicit rules.
-* Pattern Match::               How patterns match.
-* Match-Anything Rules::        Precautions you should take prior to
-                                  defining rules that can match any
-                                  target file whatever.
-* Canceling Rules::             How to override or cancel built-in rules.
-File: make.info,  Node: Pattern Intro,  Next: Pattern Examples,  Prev: Pattern Rules,  Up: Pattern Rules
-Introduction to Pattern Rules
------------------------------
-A pattern rule contains the character `%' (exactly one of them) in the
-target; otherwise, it looks exactly like an ordinary rule.  The target
-is a pattern for matching file names; the `%' matches any nonempty
-substring, while other characters match only themselves.
-   For example, `%.c' as a pattern matches any file name that ends in
-`.c'.  `s.%.c' as a pattern matches any file name that starts with
-`s.', ends in `.c' and is at least five characters long.  (There must
-be at least one character to match the `%'.)  The substring that the
-`%' matches is called the "stem".
-   `%' in a prerequisite of a pattern rule stands for the same stem
-that was matched by the `%' in the target.  In order for the pattern
-rule to apply, its target pattern must match the file name under
-consideration, and its prerequisite patterns must name files that exist
-or can be made.  These files become prerequisites of the target.
-   Thus, a rule of the form
-     %.o : %.c ; COMMAND...
-specifies how to make a file `N.o', with another file `N.c' as its
-prerequisite, provided that `N.c' exists or can be made.
-   There may also be prerequisites that do not use `%'; such a
-prerequisite attaches to every file made by this pattern rule.  These
-unvarying prerequisites are useful occasionally.
-   A pattern rule need not have any prerequisites that contain `%', or
-in fact any prerequisites at all.  Such a rule is effectively a general
-wildcard.  It provides a way to make any file that matches the target
-pattern.  *Note Last Resort::.
-   Pattern rules may have more than one target.  Unlike normal rules,
-this does not act as many different rules with the same prerequisites
-and commands.  If a pattern rule has multiple targets, `make' knows that
-the rule's commands are responsible for making all of the targets.  The
-commands are executed only once to make all the targets.  When searching
-for a pattern rule to match a target, the target patterns of a rule
-other than the one that matches the target in need of a rule are
-incidental: `make' worries only about giving commands and prerequisites
-to the file presently in question.  However, when this file's commands
-are run, the other targets are marked as having been updated themselves.
-   The order in which pattern rules appear in the makefile is important
-since this is the order in which they are considered.  Of equally
-applicable rules, only the first one found is used.  The rules you
-write take precedence over those that are built in.  Note however, that
-a rule whose prerequisites actually exist or are mentioned always takes
-priority over a rule with prerequisites that must be made by chaining
-other implicit rules.
-File: make.info,  Node: Pattern Examples,  Next: Automatic Variables,  Prev: Pattern Intro,  Up: Pattern Rules
-Pattern Rule Examples
----------------------
-Here are some examples of pattern rules actually predefined in `make'.
-First, the rule that compiles `.c' files into `.o' files:
-     %.o : %.c
-             $(CC) -c $(CFLAGS) $(CPPFLAGS) $< -o $@
-defines a rule that can make any file `X.o' from `X.c'.  The command
-uses the automatic variables `$@' and `$<' to substitute the names of
-the target file and the source file in each case where the rule applies
-(*note Automatic Variables::).
-   Here is a second built-in rule:
-     % :: RCS/%,v
-             $(CO) $(COFLAGS) $<
-defines a rule that can make any file `X' whatsoever from a
-corresponding file `X,v' in the subdirectory `RCS'.  Since the target
-is `%', this rule will apply to any file whatever, provided the
-appropriate prerequisite file exists.  The double colon makes the rule
-"terminal", which means that its prerequisite may not be an intermediate
-file (*note Match-Anything Pattern Rules: Match-Anything Rules.).
-   This pattern rule has two targets:
-     %.tab.c %.tab.h: %.y
-             bison -d $<
-This tells `make' that the command `bison -d X.y' will make both
-`X.tab.c' and `X.tab.h'.  If the file `foo' depends on the files
-`parse.tab.o' and `scan.o' and the file `scan.o' depends on the file
-`parse.tab.h', when `parse.y' is changed, the command `bison -d parse.y'
-will be executed only once, and the prerequisites of both `parse.tab.o'
-and `scan.o' will be satisfied.  (Presumably the file `parse.tab.o'
-will be recompiled from `parse.tab.c' and the file `scan.o' from
-`scan.c', while `foo' is linked from `parse.tab.o', `scan.o', and its
-other prerequisites, and it will execute happily ever after.)
-File: make.info,  Node: Automatic Variables,  Next: Pattern Match,  Prev: Pattern Examples,  Up: Pattern Rules
-Automatic Variables
--------------------
-Suppose you are writing a pattern rule to compile a `.c' file into a
-`.o' file: how do you write the `cc' command so that it operates on the
-right source file name?  You cannot write the name in the command,
-because the name is different each time the implicit rule is applied.
-   What you do is use a special feature of `make', the "automatic
-variables".  These variables have values computed afresh for each rule
-that is executed, based on the target and prerequisites of the rule.
-In this example, you would use `$@' for the object file name and `$<'
-for the source file name.
-   It's very important that you recognize the limited scope in which
-automatic variable values are available: they only have values within
-the command script.  In particular, you cannot use them anywhere within
-the target or prerequisite lists of a rule; they have no value there
-and will expand to the empty string.  A common mistake is attempting to
-use `$@' within the prerequisites list in a rule; this will not work.
-However, see below for information on the SysV-style `$$@' variables.
-   Here is a table of automatic variables:
-`$@'
-     The file name of the target of the rule.  If the target is an
-     archive member, then `$@' is the name of the archive file.  In a
-     pattern rule that has multiple targets (*note Introduction to
-     Pattern Rules: Pattern Intro.), `$@' is the name of whichever
-     target caused the rule's commands to be run.
-`$%'
-     The target member name, when the target is an archive member.
-     *Note Archives::.  For example, if the target is `foo.a(bar.o)'
-     then `$%' is `bar.o' and `$@' is `foo.a'.  `$%' is empty when the
-     target is not an archive member.
-`$<'
-     The name of the first prerequisite.  If the target got its
-     commands from an implicit rule, this will be the first
-     prerequisite added by the implicit rule (*note Implicit Rules::).
-`$?'
-     The names of all the prerequisites that are newer than the target,
-     with spaces between them.  For prerequisites which are archive
-     members, only the member named is used (*note Archives::).
-`$^'
-     The names of all the prerequisites, with spaces between them.  For
-     prerequisites which are archive members, only the member named is
-     used (*note Archives::).  A target has only one prerequisite on
-     each other file it depends on, no matter how many times each file
-     is listed as a prerequisite.  So if you list a prerequisite more
-     than once for a target, the value of `$^' contains just one copy
-     of the name.
-`$+'
-     This is like `$^', but prerequisites listed more than once are
-     duplicated in the order they were listed in the makefile.  This is
-     primarily useful for use in linking commands where it is
-     meaningful to repeat library file names in a particular order.
-`$*'
-     The stem with which an implicit rule matches (*note How Patterns
-     Match: Pattern Match.).  If the target is `dir/a.foo.b' and the
-     target pattern is `a.%.b' then the stem is `dir/foo'.  The stem is
-     useful for constructing names of related files.
-     In a static pattern rule, the stem is part of the file name that
-     matched the `%' in the target pattern.
-     In an explicit rule, there is no stem; so `$*' cannot be determined
-     in that way.  Instead, if the target name ends with a recognized
-     suffix (*note Old-Fashioned Suffix Rules: Suffix Rules.), `$*' is
-     set to the target name minus the suffix.  For example, if the
-     target name is `foo.c', then `$*' is set to `foo', since `.c' is a
-     suffix.  GNU `make' does this bizarre thing only for compatibility
-     with other implementations of `make'.  You should generally avoid
-     using `$*' except in implicit rules or static pattern rules.
-     If the target name in an explicit rule does not end with a
-     recognized suffix, `$*' is set to the empty string for that rule.
-   `$?' is useful even in explicit rules when you wish to operate on
-only the prerequisites that have changed.  For example, suppose that an
-archive named `lib' is supposed to contain copies of several object
-files.  This rule copies just the changed object files into the archive:
-     lib: foo.o bar.o lose.o win.o
-             ar r lib $?
-   Of the variables listed above, four have values that are single file
-names, and three have values that are lists of file names.  These seven
-have variants that get just the file's directory name or just the file
-name within the directory.  The variant variables' names are formed by
-appending `D' or `F', respectively.  These variants are semi-obsolete
-in GNU `make' since the functions `dir' and `notdir' can be used to get
-a similar effect (*note Functions for File Names: File Name
-Functions.).  Note, however, that the `D' variants all omit the
-trailing slash which always appears in the output of the `dir'
-function.  Here is a table of the variants:
-`$(@D)'
-     The directory part of the file name of the target, with the
-     trailing slash removed.  If the value of `$@' is `dir/foo.o' then
-     `$(@D)' is `dir'.  This value is `.' if `$@' does not contain a
-     slash.
-`$(@F)'
-     The file-within-directory part of the file name of the target.  If
-     the value of `$@' is `dir/foo.o' then `$(@F)' is `foo.o'.  `$(@F)'
-     is equivalent to `$(notdir $@)'.
-`$(*D)'
-`$(*F)'
-     The directory part and the file-within-directory part of the stem;
-     `dir' and `foo' in this example.
-`$(%D)'
-`$(%F)'
-     The directory part and the file-within-directory part of the target
-     archive member name.  This makes sense only for archive member
-     targets of the form `ARCHIVE(MEMBER)' and is useful only when
-     MEMBER may contain a directory name.  (*Note Archive Members as
-     Targets: Archive Members.)
-`$(<D)'
-`$(<F)'
-     The directory part and the file-within-directory part of the first
-     prerequisite.
-`$(^D)'
-`$(^F)'
-     Lists of the directory parts and the file-within-directory parts
-     of all prerequisites.
-`$(+D)'
-`$(+F)'
-     Lists of the directory parts and the file-within-directory parts
-     of all prerequisites, including multiple instances of duplicated
-     prerequisites.
-`$(?D)'
-`$(?F)'
-     Lists of the directory parts and the file-within-directory parts of
-     all prerequisites that are newer than the target.
-   Note that we use a special stylistic convention when we talk about
-these automatic variables; we write "the value of `$<'", rather than
-"the variable `<'" as we would write for ordinary variables such as
-`objects' and `CFLAGS'.  We think this convention looks more natural in
-this special case.  Please do not assume it has a deep significance;
-`$<' refers to the variable named `<' just as `$(CFLAGS)' refers to the
-variable named `CFLAGS'.  You could just as well use `$(<)' in place of
-`$<'.
-   GNU `make' provides support for the SysV `make' feature that allows
-special variable references `$$@', `$$(@D)', and `$$(@F)' (note the
-required double-"$"!) to appear with the _prerequisites list_ (normal
-automatic variables are available only within a command script).  When
-appearing in a prerequisites list, these variables are expanded to the
-name of the target, the directory component of the target, and the file
-component of the target, respectively.
-   Note that these variables are available only within explicit and
-static pattern (*note Static Pattern Rules: Static Pattern.) rules;
-they have no special significance within implicit (suffix or pattern)
-rules.  Also note that while SysV `make' actually expands its entire
-prerequisite list _twice_, GNU `make' does not behave this way: instead
-it simply expands these special variables without re-expanding any
-other part of the prerequisites list.
-   This somewhat bizarre feature is included only to provide some
-compatibility with SysV makefiles.  In a native GNU `make' file there
-are other ways to accomplish the same results.  This feature is
-disabled if the special pseudo target `.POSIX' is defined.
-File: make.info,  Node: Pattern Match,  Next: Match-Anything Rules,  Prev: Automatic Variables,  Up: Pattern Rules
-How Patterns Match
-------------------
-A target pattern is composed of a `%' between a prefix and a suffix,
-either or both of which may be empty.  The pattern matches a file name
-only if the file name starts with the prefix and ends with the suffix,
-without overlap.  The text between the prefix and the suffix is called
-the "stem".  Thus, when the pattern `%.o' matches the file name
-`test.o', the stem is `test'.  The pattern rule prerequisites are
-turned into actual file names by substituting the stem for the character
-`%'.  Thus, if in the same example one of the prerequisites is written
-as `%.c', it expands to `test.c'.
-   When the target pattern does not contain a slash (and it usually does
-not), directory names in the file names are removed from the file name
-before it is compared with the target prefix and suffix.  After the
-comparison of the file name to the target pattern, the directory names,
-along with the slash that ends them, are added on to the prerequisite
-file names generated from the pattern rule's prerequisite patterns and
-the file name. The directories are ignored only for the purpose of
-finding an implicit rule to use, not in the application of that rule.
-Thus, `e%t' matches the file name `src/eat', with `src/a' as the stem.
-When prerequisites are turned into file names, the directories from the
-stem are added at the front, while the rest of the stem is substituted
-for the `%'.  The stem `src/a' with a prerequisite pattern `c%r' gives
-the file name `src/car'.
-File: make.info,  Node: Match-Anything Rules,  Next: Canceling Rules,  Prev: Pattern Match,  Up: Pattern Rules
-Match-Anything Pattern Rules
-----------------------------
-When a pattern rule's target is just `%', it matches any file name
-whatever.  We call these rules "match-anything" rules.  They are very
-useful, but it can take a lot of time for `make' to think about them,
-because it must consider every such rule for each file name listed
-either as a target or as a prerequisite.
-   Suppose the makefile mentions `foo.c'.  For this target, `make'
-would have to consider making it by linking an object file `foo.c.o',
-or by C compilation-and-linking in one step from `foo.c.c', or by
-Pascal compilation-and-linking from `foo.c.p', and many other
-possibilities.
-   We know these possibilities are ridiculous since `foo.c' is a C
-source file, not an executable.  If `make' did consider these
-possibilities, it would ultimately reject them, because files such as
-`foo.c.o' and `foo.c.p' would not exist.  But these possibilities are so
-numerous that `make' would run very slowly if it had to consider them.
-   To gain speed, we have put various constraints on the way `make'
-considers match-anything rules.  There are two different constraints
-that can be applied, and each time you define a match-anything rule you
-must choose one or the other for that rule.
-   One choice is to mark the match-anything rule as "terminal" by
-defining it with a double colon.  When a rule is terminal, it does not
-apply unless its prerequisites actually exist.  Prerequisites that
-could be made with other implicit rules are not good enough.  In other
-words, no further chaining is allowed beyond a terminal rule.
-   For example, the built-in implicit rules for extracting sources from
-RCS and SCCS files are terminal; as a result, if the file `foo.c,v' does
-not exist, `make' will not even consider trying to make it as an
-intermediate file from `foo.c,v.o' or from `RCS/SCCS/s.foo.c,v'.  RCS
-and SCCS files are generally ultimate source files, which should not be
-remade from any other files; therefore, `make' can save time by not
-looking for ways to remake them.
-   If you do not mark the match-anything rule as terminal, then it is
-nonterminal.  A nonterminal match-anything rule cannot apply to a file
-name that indicates a specific type of data.  A file name indicates a
-specific type of data if some non-match-anything implicit rule target
-matches it.
-   For example, the file name `foo.c' matches the target for the pattern
-rule `%.c : %.y' (the rule to run Yacc).  Regardless of whether this
-rule is actually applicable (which happens only if there is a file
-`foo.y'), the fact that its target matches is enough to prevent
-consideration of any nonterminal match-anything rules for the file
-`foo.c'.  Thus, `make' will not even consider trying to make `foo.c' as
-an executable file from `foo.c.o', `foo.c.c', `foo.c.p', etc.
-   The motivation for this constraint is that nonterminal match-anything
-rules are used for making files containing specific types of data (such
-as executable files) and a file name with a recognized suffix indicates
-some other specific type of data (such as a C source file).
-   Special built-in dummy pattern rules are provided solely to recognize
-certain file names so that nonterminal match-anything rules will not be
-considered.  These dummy rules have no prerequisites and no commands,
-and they are ignored for all other purposes.  For example, the built-in
-implicit rule
-     %.p :
-exists to make sure that Pascal source files such as `foo.p' match a
-specific target pattern and thereby prevent time from being wasted
-looking for `foo.p.o' or `foo.p.c'.
-   Dummy pattern rules such as the one for `%.p' are made for every
-suffix listed as valid for use in suffix rules (*note Old-Fashioned
-Suffix Rules: Suffix Rules.).
-File: make.info,  Node: Canceling Rules,  Prev: Match-Anything Rules,  Up: Pattern Rules
-Canceling Implicit Rules
-------------------------
-You can override a built-in implicit rule (or one you have defined
-yourself) by defining a new pattern rule with the same target and
-prerequisites, but different commands.  When the new rule is defined,
-the built-in one is replaced.  The new rule's position in the sequence
-of implicit rules is determined by where you write the new rule.
-   You can cancel a built-in implicit rule by defining a pattern rule
-with the same target and prerequisites, but no commands.  For example,
-the following would cancel the rule that runs the assembler:
-     %.o : %.s
-File: make.info,  Node: Last Resort,  Next: Suffix Rules,  Prev: Pattern Rules,  Up: Implicit Rules
-Defining Last-Resort Default Rules
-==================================
-You can define a last-resort implicit rule by writing a terminal
-match-anything pattern rule with no prerequisites (*note Match-Anything
-Rules::).  This is just like any other pattern rule; the only thing
-special about it is that it will match any target.  So such a rule's
-commands are used for all targets and prerequisites that have no
-commands of their own and for which no other implicit rule applies.
-   For example, when testing a makefile, you might not care if the
-source files contain real data, only that they exist.  Then you might
-do this:
-     %::
-             touch $@
-to cause all the source files needed (as prerequisites) to be created
-automatically.
-   You can instead define commands to be used for targets for which
-there are no rules at all, even ones which don't specify commands.  You
-do this by writing a rule for the target `.DEFAULT'.  Such a rule's
-commands are used for all prerequisites which do not appear as targets
-in any explicit rule, and for which no implicit rule applies.
-Naturally, there is no `.DEFAULT' rule unless you write one.
-   If you use `.DEFAULT' with no commands or prerequisites:
-     .DEFAULT:
-the commands previously stored for `.DEFAULT' are cleared.  Then `make'
-acts as if you had never defined `.DEFAULT' at all.
-   If you do not want a target to get the commands from a match-anything
-pattern rule or `.DEFAULT', but you also do not want any commands to be
-run for the target, you can give it empty commands (*note Defining
-Empty Commands: Empty Commands.).
-   You can use a last-resort rule to override part of another makefile.
-*Note Overriding Part of Another Makefile: Overriding Makefiles.
-File: make.info,  Node: Suffix Rules,  Next: Implicit Rule Search,  Prev: Last Resort,  Up: Implicit Rules
-Old-Fashioned Suffix Rules
-==========================
-"Suffix rules" are the old-fashioned way of defining implicit rules for
-`make'.  Suffix rules are obsolete because pattern rules are more
-general and clearer.  They are supported in GNU `make' for
-compatibility with old makefiles.  They come in two kinds:
-"double-suffix" and "single-suffix".
-   A double-suffix rule is defined by a pair of suffixes: the target
-suffix and the source suffix.  It matches any file whose name ends with
-the target suffix.  The corresponding implicit prerequisite is made by
-replacing the target suffix with the source suffix in the file name.  A
-two-suffix rule whose target and source suffixes are `.o' and `.c' is
-equivalent to the pattern rule `%.o : %.c'.
-   A single-suffix rule is defined by a single suffix, which is the
-source suffix.  It matches any file name, and the corresponding implicit
-prerequisite name is made by appending the source suffix.  A
-single-suffix rule whose source suffix is `.c' is equivalent to the
-pattern rule `% : %.c'.
-   Suffix rule definitions are recognized by comparing each rule's
-target against a defined list of known suffixes.  When `make' sees a
-rule whose target is a known suffix, this rule is considered a
-single-suffix rule.  When `make' sees a rule whose target is two known
-suffixes concatenated, this rule is taken as a double-suffix rule.
-   For example, `.c' and `.o' are both on the default list of known
-suffixes.  Therefore, if you define a rule whose target is `.c.o',
-`make' takes it to be a double-suffix rule with source suffix `.c' and
-target suffix `.o'.  Here is the old-fashioned way to define the rule
-for compiling a C source file:
-     .c.o:
-             $(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<
-   Suffix rules cannot have any prerequisites of their own.  If they
-have any, they are treated as normal files with funny names, not as
-suffix rules.  Thus, the rule:
-     .c.o: foo.h
-             $(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<
-tells how to make the file `.c.o' from the prerequisite file `foo.h',
-and is not at all like the pattern rule:
-     %.o: %.c foo.h
-             $(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<
-which tells how to make `.o' files from `.c' files, and makes all `.o'
-files using this pattern rule also depend on `foo.h'.
-   Suffix rules with no commands are also meaningless.  They do not
-remove previous rules as do pattern rules with no commands (*note
-Canceling Implicit Rules: Canceling Rules.).  They simply enter the
-suffix or pair of suffixes concatenated as a target in the data base.
-   The known suffixes are simply the names of the prerequisites of the
-special target `.SUFFIXES'.  You can add your own suffixes by writing a
-rule for `.SUFFIXES' that adds more prerequisites, as in:
-     .SUFFIXES: .hack .win
-which adds `.hack' and `.win' to the end of the list of suffixes.
-   If you wish to eliminate the default known suffixes instead of just
-adding to them, write a rule for `.SUFFIXES' with no prerequisites.  By
-special dispensation, this eliminates all existing prerequisites of
-`.SUFFIXES'.  You can then write another rule to add the suffixes you
-want.  For example,
-     .SUFFIXES:            # Delete the default suffixes
-     .SUFFIXES: .c .o .h   # Define our suffix list
-   The `-r' or `--no-builtin-rules' flag causes the default list of
-suffixes to be empty.
-   The variable `SUFFIXES' is defined to the default list of suffixes
-before `make' reads any makefiles.  You can change the list of suffixes
-with a rule for the special target `.SUFFIXES', but that does not alter
-this variable.

Note: See TracChangeset for help on using the changeset viewer.

Context Navigation

Changeset 501 for vendor/gnumake/current/doc/make.info-1

Legend:

vendor/gnumake/current/doc/make.info-1

Download in other formats: