source: vendor/gcc/3.2.2/libf2c/libI77/README.netlib

If your compiler does not recognize ANSI C headers,
compile with KR_headers defined:  either add -DKR_headers
to the definition of CFLAGS in the makefile, or insert

#define KR_headers

at the top of f2c.h and fmtlib.c .


If you have a really ancient K&R C compiler that does not understand
void, add -Dvoid=int to the definition of CFLAGS in the makefile.

If you use a C++ compiler, first create a local f2c.h by appending
f2ch.add to the usual f2c.h, e.g., by issuing the command
        make f2c.h
which assumes f2c.h is installed in /usr/include .

If your system lacks /usr/include/fcntl.h , then you
should simply create an empty fcntl.h in this directory.
If your compiler then complains about creat and open not
having a prototype, compile with OPEN_DECL defined.
On many systems, open and creat are declared in fcntl.h .

If your system has /usr/include/fcntl.h, you may need to add
-D_POSIX_SOURCE to the makefile's definition of CFLAGS.

If your system's sprintf does not work the way ANSI C
specifies -- specifically, if it does not return the
number of characters transmitted -- then insert the line

#define USE_STRLEN

at the end of fmt.h .  This is necessary with
at least some versions of Sun and DEC software.
In particular, if you get a warning about an improper
pointer/integer combination in compiling wref.c, then
you need to compile with -DUSE_STRLEN .

If your system's fopen does not like the ANSI binary
reading and writing modes "rb" and "wb", then you should
compile open.c with NON_ANSI_RW_MODES #defined.

If you get error messages about references to cf->_ptr
and cf->_base when compiling wrtfmt.c and wsfe.c or to
stderr->_flag when compiling err.c, then insert the line

#define NON_UNIX_STDIO

at the beginning of fio.h, and recompile everything (or
at least those modules that contain NON_UNIX_STDIO).

Unformatted sequential records consist of a length of record
contents, the record contents themselves, and the length of
record contents again (for backspace).  Prior to 17 Oct. 1991,
the length was of type int; now it is of type long, but you
can change it back to int by inserting

#define UIOLEN_int

at the beginning of fio.h.  This affects only sue.c and uio.c .

On VAX, Cray, or Research Tenth-Edition Unix systems, you may
need to add -DVAX, -DCRAY, or -DV10 (respectively) to CFLAGS
to make fp.h work correctly.  Alternatively, you may need to
edit fp.h to suit your machine.

You may need to supply the following non-ANSI routines:

  fstat(int fileds, struct stat *buf) is similar
to stat(char *name, struct stat *buf), except that
the first argument, fileds, is the file descriptor
returned by open rather than the name of the file.
fstat is used in the system-dependent routine
canseek (in the libI77 source file err.c), which
is supposed to return 1 if it's possible to issue
seeks on the file in question, 0 if it's not; you may
need to suitably modify err.c .  On non-UNIX systems,
you can avoid references to fstat and stat by compiling
with NON_UNIX_STDIO defined; in that case, you may need
to supply access(char *Name,0), which is supposed to
return 0 if file Name exists, nonzero otherwise.

  char * mktemp(char *buf) is supposed to replace the
6 trailing X's in buf with a unique number and then
return buf.  The idea is to get a unique name for
a temporary file.

On non-UNIX systems, you may need to change a few other,
e.g.: the form of name computed by mktemp() in endfile.c and
open.c; the use of the open(), close(), and creat() system
calls in endfile.c, err.c, open.c; and the modes in calls on
fopen() and fdopen() (and perhaps the use of fdopen() itself
-- it's supposed to return a FILE* corresponding to a given
an integer file descriptor) in err.c and open.c (component ufmt
of struct unit is 1 for formatted I/O -- text mode on some systems
-- and 0 for unformatted I/O -- binary mode on some systems).
Compiling with -DNON_UNIX_STDIO omits all references to creat()
and almost all references to open() and close(), the exception
being in the function f__isdev() (in open.c).

For MS-DOS, compile all of libI77 with -DMSDOS (which implies
-DNON_UNIX_STDIO).  You may need to make other compiler-dependent
adjustments; for example, for Turbo C++ you need to adjust the mktemp
invocations and to #undef ungetc in lread.c and rsne.c .

If you want to be able to load against libI77 but not libF77,
then you will need to add sig_die.o (from libF77) to libI77.

If you wish to use translated Fortran that has funny notions
of record length for direct unformatted I/O (i.e., that assumes
RECL= values in OPEN statements are not bytes but rather counts
of some other units -- e.g., 4-character words for VMS), then you
should insert an appropriate #define for url_Adjust at the
beginning of open.c .  For VMS Fortran, for example,
#define url_Adjust(x) x *= 4
would suffice.

To check for transmission errors, issue the command
        make check
This assumes you have the xsum program whose source, xsum.c,
is distributed as part of "all from f2c/src".  If you do not
have xsum, you can obtain xsum.c by sending the following E-mail
message to netlib@netlib.bell-labs.com
        send xsum.c from f2c/src

The makefile assumes you have installed f2c.h in a standard
place (and does not cause recompilation when f2c.h is changed);
f2c.h comes with "all from f2c" (the source for f2c) and is
available separately ("f2c.h from f2c").

By default, Fortran I/O units 5, 6, and 0 are pre-connected to
stdin, stdout, and stderr, respectively.  You can change this
behavior by changing f_init() in err.c to suit your needs.
Note that f2c assumes READ(*... means READ(5... and WRITE(*...
means WRITE(6... .  Moreover, an OPEN(n,... statement that does
not specify a file name (and does not specify STATUS='SCRATCH')
assumes FILE='fort.n' .  You can change this by editing open.c
and endfile.c suitably.

Unless you adjust the "#define MXUNIT" line in fio.h, Fortran units
0, 1, ..., 99 are available, i.e., the highest allowed unit number
is MXUNIT - 1.

Lines protected from compilation by #ifdef Allow_TYQUAD
are for a possible extension to 64-bit integers in which
integer = int = 32 bits and longint = long = 64 bits.

Extensions (Feb. 1993) to NAMELIST processing:
 1. Reading a ? instead of &name (the start of a namelist) causes
the namelist being sought to be written to stdout (unit 6);
to omit this feature, compile rsne.c with -DNo_Namelist_Questions.
 2. Reading the wrong namelist name now leads to an error message
and an attempt to skip input until the right namelist name is found;
to omit this feature, compile rsne.c with -DNo_Bad_Namelist_Skip.
 3. Namelist writes now insert newlines before each variable; to omit
this feature, compile xwsne.c with -DNo_Extra_Namelist_Newlines.
 4. (Sept. 1995) When looking for the &name that starts namelist
input, lines whose first non-blank character is something other
than &, $, or ? are treated as comment lines and ignored, unless
rsne.c is compiled with -DNo_Namelist_Comments.

Nonstandard extension (Feb. 1993) to open: for sequential files,
ACCESS='APPEND' (or access='anything else starting with "A" or "a"')
causes the file to be positioned at end-of-file, so a write will
append to the file.

Some buggy Fortran programs use unformatted direct I/O to write
an incomplete record and later read more from that record than
they have written.  For records other than the last, the unwritten
portion of the record reads as binary zeros.  The last record is
a special case: attempting to read more from it than was written
gives end-of-file -- which may help one find a bug.  Some other
Fortran I/O libraries treat the last record no differently than
others and thus give no help in finding the bug of reading more
than was written.  If you wish to have this behavior, compile
uio.c with -DPad_UDread .

If you want to be able to catch write failures (e.g., due to a
disk being full) with an ERR= specifier, compile dfe.c, due.c,
sfe.c, sue.c, and wsle.c with -DALWAYS_FLUSH.  This will lead to
slower execution and more I/O, but should make ERR= work as
expected, provided fflush returns an error return when its
physical write fails.

Carriage controls are meant to be interpreted by the UNIX col
program (or a similar program).  Sometimes it's convenient to use
only ' ' as the carriage control character (normal single spacing).
If you compile lwrite.c and wsfe.c with -DOMIT_BLANK_CC, formatted
external output lines will have an initial ' ' quietly omitted,
making use of the col program unnecessary with output that only
has ' ' for carriage control.

The Fortran 77 Standard leaves it up to the implementation whether
formatted writes of floating-point numbers of absolute value < 1 have
a zero before the decimal point.  By default, libI77 omits such
superfluous zeros, but you can cause them to appear by compiling
lwrite.c, wref.c, and wrtfmt.c with -DWANT_LEAD_0 .

If your system lacks a ranlib command, you don't need it.
Either comment out the makefile's ranlib invocation, or install
a harmless "ranlib" command somewhere in your PATH, such as the
one-line shell script

        exit 0

or (on some systems)

        exec /usr/bin/ar lts $1 >/dev/null

Most of the routines in libI77 are support routines for Fortran
I/O.  There are a few exceptions, summarized below -- I/O related
functions and subroutines that appear to your program as ordinary
external Fortran routines.

1.      CALL FLUSH flushes all buffers.

2.      FTELL(i) is an INTEGER function that returns the current
        offset of Fortran unit i (or -1 if unit i is not open).

3.      CALL FSEEK(i, offset, whence, *errlab) attemps to move
        Fortran unit i to the specified offset: absolute offset
        if whence = 0; relative to the current offset if whence = 1;
        relative to the end of the file if whence = 2.  It branches
        to label errlab if unit i is not open or if the call
        otherwise fails.