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emacs/m4/fstatat.m4
2024-05-11 18:46:26 -07:00

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# fstatat.m4
# serial 5
dnl Copyright (C) 2004-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# Written by Jim Meyering.
# If we have the fstatat function, and it has the bug (in AIX 7.1)
# that it does not fill in st_size correctly, use the replacement function.
AC_DEFUN([gl_FUNC_FSTATAT],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK])
AC_REQUIRE([AC_CANONICAL_HOST])
AC_CHECK_FUNCS_ONCE([fstatat])
if test $ac_cv_func_fstatat = no; then
HAVE_FSTATAT=0
else
dnl Test for an AIX 7.1 bug; see
dnl <https://lists.gnu.org/r/bug-tar/2011-09/msg00015.html>.
AC_CACHE_CHECK([whether fstatat (..., 0) works],
[gl_cv_func_fstatat_zero_flag],
[AC_RUN_IFELSE(
[AC_LANG_SOURCE(
[[
#include <fcntl.h>
#include <sys/stat.h>
int
main (void)
{
struct stat a;
return fstatat (AT_FDCWD, ".", &a, 0) != 0;
}
]])],
[gl_cv_func_fstatat_zero_flag=yes],
[gl_cv_func_fstatat_zero_flag=no],
[case "$host_os" in
aix*) gl_cv_func_fstatat_zero_flag="guessing no";;
*) gl_cv_func_fstatat_zero_flag="guessing yes";;
esac
])
])
case $gl_cv_func_fstatat_zero_flag+$gl_cv_func_lstat_dereferences_slashed_symlink in
*yes+*yes) ;;
*) REPLACE_FSTATAT=1 ;;
esac
case $host_os in
darwin* | solaris*)
REPLACE_FSTATAT=1 ;;
esac
case $REPLACE_FSTATAT,$gl_cv_func_fstatat_zero_flag in
1,*yes)
AC_DEFINE([HAVE_WORKING_FSTATAT_ZERO_FLAG], [1],
[Define to 1 if fstatat (..., 0) works.
For example, it does not work in AIX 7.1.])
;;
esac
fi
])