1
0
mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-25 10:47:00 +00:00
emacs/m4/pselect.m4
Paul Eggert 3128d5d10e Merge from gnulib
This incorporates:
2017-07-13 Improve cross-compilation guesses for native Windows
2017-07-11 More systematic m4 quoting and indentation
2017-07-10 Make sure $host and $host_os are defined when used
2017-07-03 stdioext: Port to OpenVMS
2017-06-24 xalloc-oversized: port to icc
* doc/misc/texinfo.tex, lib/fpending.c, lib/stdio-impl.h:
* lib/xalloc-oversized.h, m4/dirfd.m4, m4/gettimeofday.m4:
* m4/lstat.m4, m4/mktime.m4, m4/pselect.m4, m4/putenv.m4:
* m4/stdint.m4, m4/strtoimax.m4, m4/utimes.m4:
Copy from Gnulib.
2017-07-13 19:24:49 -07:00

71 lines
2.2 KiB
Plaintext

# pselect.m4 serial 4
dnl Copyright (C) 2011-2017 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_PSELECT],
[
AC_REQUIRE([gl_HEADER_SYS_SELECT])
AC_REQUIRE([AC_C_RESTRICT])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([pselect])
if test $ac_cv_func_pselect = yes; then
AC_CACHE_CHECK([whether signature of pselect conforms to POSIX],
[gl_cv_sig_pselect],
[AC_LINK_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/select.h>
]],
[[int (*p) (int, fd_set *, fd_set *, fd_set *restrict,
struct timespec const *restrict,
sigset_t const *restrict) = pselect;
return !p;]])],
[gl_cv_sig_pselect=yes],
[gl_cv_sig_pselect=no])])
dnl On FreeBSD 8.2, pselect() doesn't always reject bad fds.
AC_CACHE_CHECK([whether pselect detects invalid fds],
[gl_cv_func_pselect_detects_ebadf],
[
AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <sys/types.h>
#include <sys/time.h>
#if HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <unistd.h>
#include <errno.h>
]],[[
fd_set set;
dup2(0, 16);
FD_ZERO(&set);
FD_SET(16, &set);
close(16);
struct timespec timeout;
timeout.tv_sec = 0;
timeout.tv_nsec = 5000;
return pselect (17, &set, NULL, NULL, &timeout, NULL) != -1 || errno != EBADF;
]])], [gl_cv_func_pselect_detects_ebadf=yes],
[gl_cv_func_pselect_detects_ebadf=no],
[
case "$host_os" in
# Guess yes on glibc systems.
*-gnu*) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
# If we don't know, assume the worst.
*) gl_cv_func_pselect_detects_ebadf="guessing no" ;;
esac
])
])
case $gl_cv_func_pselect_detects_ebadf in
*yes) ;;
*) REPLACE_PSELECT=1 ;;
esac
fi
if test $ac_cv_func_pselect = no || test $gl_cv_sig_pselect = no; then
REPLACE_PSELECT=1
fi
])