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

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# open-slash.m4
# serial 2
dnl Copyright (C) 2007-2024 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.
dnl Tests whether open() and creat() recognize a trailing slash.
dnl Sets gl_cv_func_open_slash.
AC_DEFUN([gl_OPEN_TRAILING_SLASH_BUG],
[
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
dnl open("foo/") should not create a file when the file name has a
dnl trailing slash. FreeBSD only has the problem on symlinks.
AC_CHECK_FUNCS_ONCE([lstat])
AC_CACHE_CHECK([whether open recognizes a trailing slash],
[gl_cv_func_open_slash],
[# Assume that if we have lstat, we can also check symlinks.
if test $ac_cv_func_lstat = yes; then
touch conftest.tmp
ln -s conftest.tmp conftest.lnk
fi
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <fcntl.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
]GL_MDA_DEFINES[
int main ()
{
int result = 0;
#if HAVE_LSTAT
if (open ("conftest.lnk/", O_RDONLY) != -1)
result |= 1;
#endif
if (open ("conftest.sl/", O_CREAT, 0600) >= 0)
result |= 2;
return result;
}]])],
[gl_cv_func_open_slash=yes],
[gl_cv_func_open_slash=no],
[
changequote(,)dnl
case "$host_os" in
freebsd* | aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
gl_cv_func_open_slash="guessing no" ;;
*)
gl_cv_func_open_slash="guessing yes" ;;
esac
changequote([,])dnl
])
rm -f conftest.sl conftest.tmp conftest.lnk
])
case "$gl_cv_func_open_slash" in
*no)
AC_DEFINE([OPEN_TRAILING_SLASH_BUG], [1],
[Define to 1 if open() fails to recognize a trailing slash.])
;;
esac
])