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emacs/m4/open.m4
Paul Eggert 794c3cd3a2 Merge from Gnulib; use ‘open’ for O_CLOEXEC
This incorporates:
2017-08-15 renameat: ensure declaration in <stdio.h> on NetBSD
2017-08-15 extensions: enable NetBSD specific extensions
2017-08-14 open: support O_CLOEXEC
2017-08-13 reallocarray: new module
* admin/merge-gnulib (AVOIDED_MODULES): Remove ‘open’, since
it now supports O_CLOEXEC and this simplifies Emacs.
* build-aux/config.guess, lib/fcntl.in.h, lib/stdio.in.h:
* lib/stdlib.in.h, m4/extensions.m4, m4/stdlib_h.m4:
Copy from Gnulib.
* lib/cloexec.c, lib/cloexec.h, lib/open.c:
* m4/mode_t.m4, m4/open-cloexec.m4, m4/open.m4:
New files, copied from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib-src/etags.c (O_CLOEXEC) [WINDOWSNT]:
Remove, as Gnulib does this for us.
* src/filelock.c (create_lock_file):
* src/sysdep.c (emacs_open, emacs_pipe):
Don’t worry about O_CLOEXEC == 0, as Gnulib no longer sets it to 0.
2017-08-16 14:04:33 -07:00

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# open.m4 serial 15
dnl Copyright (C) 2007-2017 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.
AC_DEFUN([gl_FUNC_OPEN],
[
AC_REQUIRE([AC_CANONICAL_HOST])
AC_REQUIRE([gl_PREPROC_O_CLOEXEC])
case "$host_os" in
mingw* | pw*)
REPLACE_OPEN=1
;;
*)
dnl open("foo/") should not create a file when the file name has a
dnl trailing slash. FreeBSD only has the problem on symlinks.
AC_CHECK_FUNCS_ONCE([lstat])
if test "$gl_cv_macro_O_CLOEXEC" != yes; then
REPLACE_OPEN=1
fi
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 $ac_cv_func_lstat = yes; then
touch conftest.tmp
ln -s conftest.tmp conftest.lnk
fi
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <fcntl.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
int main ()
{
int result = 0;
#if HAVE_LSTAT
if (open ("conftest.lnk/", O_RDONLY) != -1)
result |= 1;
#endif
if (open ("conftest.sl/", O_CREAT, 0600) >= 0)
result |= 2;
return result;
}]])],
[gl_cv_func_open_slash=yes],
[gl_cv_func_open_slash=no],
[
changequote(,)dnl
case "$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.])
REPLACE_OPEN=1
;;
esac
;;
esac
dnl Replace open() for supporting the gnulib-defined fchdir() function,
dnl to keep fchdir's bookkeeping up-to-date.
m4_ifdef([gl_FUNC_FCHDIR], [
if test $REPLACE_OPEN = 0; then
gl_TEST_FCHDIR
if test $HAVE_FCHDIR = 0; then
REPLACE_OPEN=1
fi
fi
])
dnl Replace open() for supporting the gnulib-defined O_NONBLOCK flag.
m4_ifdef([gl_NONBLOCKING_IO], [
if test $REPLACE_OPEN = 0; then
gl_NONBLOCKING_IO
if test $gl_cv_have_open_O_NONBLOCK != yes; then
REPLACE_OPEN=1
fi
fi
])
])
# Prerequisites of lib/open.c.
AC_DEFUN([gl_PREREQ_OPEN],
[
AC_REQUIRE([gl_PROMOTED_TYPE_MODE_T])
:
])