| 1 | # dup.m4 serial 7
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| 2 | dnl Copyright (C) 2011-2021 Free Software Foundation, Inc.
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| 3 | dnl This file is free software; the Free Software Foundation
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| 4 | dnl gives unlimited permission to copy and/or distribute it,
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| 5 | dnl with or without modifications, as long as this notice is preserved.
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| 6 |
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| 7 | AC_DEFUN([gl_FUNC_DUP],
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| 8 | [
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| 9 | AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
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| 10 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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| 11 | m4_ifdef([gl_MSVC_INVAL], [
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| 12 | AC_REQUIRE([gl_MSVC_INVAL])
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| 13 | if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
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| 14 | REPLACE_DUP=1
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| 15 | fi
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| 16 | ])
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| 17 | dnl Replace dup() for supporting the gnulib-defined fchdir() function,
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| 18 | dnl to keep fchdir's bookkeeping up-to-date.
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| 19 | m4_ifdef([gl_FUNC_FCHDIR], [
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| 20 | gl_TEST_FCHDIR
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| 21 | if test $HAVE_FCHDIR = 0; then
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| 22 | REPLACE_DUP=1
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| 23 | fi
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| 24 | ])
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| 25 | AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
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| 26 | [AC_RUN_IFELSE(
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| 27 | [AC_LANG_PROGRAM([[#include <unistd.h>
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| 28 | #include <fcntl.h>
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| 29 | #include <errno.h>
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| 30 | ]GL_MDA_DEFINES],
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| 31 | [[/* On OS/2 kLIBC, dup does not work on a directory fd. */
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| 32 | int fd = open (".", O_RDONLY);
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| 33 | return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
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| 34 | ]])
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| 35 | ],
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| 36 | [gl_cv_func_dup_works=yes],
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| 37 | [gl_cv_func_dup_works=no],
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| 38 | [case "$host_os" in
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| 39 | # Guess no on native Windows.
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| 40 | mingw*) gl_cv_func_dup_works="guessing no" ;;
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| 41 | *) gl_cv_func_dup_works="guessing yes" ;;
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| 42 | esac
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| 43 | ])
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| 44 | ])
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| 45 | case "$gl_cv_func_dup_works" in
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| 46 | *yes) ;;
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| 47 | *)
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| 48 | REPLACE_DUP=1
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| 49 | ;;
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| 50 | esac
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| 51 | ])
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| 52 |
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| 53 | # Prerequisites of lib/dup.c.
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| 54 | AC_DEFUN([gl_PREREQ_DUP], [:])
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