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# pselect.m4 serial 8
dnl Copyright (C) 2011-2019 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 Linux systems.
linux-* | linux) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_pselect_detects_ebadf="$gl_cross_guess_normal" ;;
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
])
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