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-rw-r--r--m4/pselect.m473
1 files changed, 73 insertions, 0 deletions
diff --git a/m4/pselect.m4 b/m4/pselect.m4
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index 0000000..8611441
--- /dev/null
+++ b/m4/pselect.m4
@@ -0,0 +1,73 @@
+# pselect.m4 serial 10
+dnl Copyright (C) 2011-2022 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_SYS_SELECT_H])
+ AC_REQUIRE([AC_C_RESTRICT])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CHECK_FUNCS_ONCE([pselect])
+
+ if test $ac_cv_func_pselect = yes; then
+ AC_CACHE_CHECK([whether signature of pselect conforms to POSIX],
+ [gl_cv_sig_pselect],
+ [AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <sys/select.h>
+ ]],
+ [[int (*p) (int, fd_set *, fd_set *, fd_set *restrict,
+ struct timespec const *restrict,
+ sigset_t const *restrict) = pselect;
+ return !p;]])],
+ [gl_cv_sig_pselect=yes],
+ [gl_cv_sig_pselect=no])])
+
+ dnl On FreeBSD 8.2, pselect() doesn't always reject bad fds.
+ AC_CACHE_CHECK([whether pselect detects invalid fds],
+ [gl_cv_func_pselect_detects_ebadf],
+ [
+ AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/time.h>
+#if HAVE_SYS_SELECT_H
+# include <sys/select.h>
+#endif
+#include <unistd.h>
+#include <errno.h>
+]GL_MDA_DEFINES],
+[[
+ fd_set set;
+ dup2(0, 16);
+ FD_ZERO(&set);
+ FD_SET(16, &set);
+ close(16);
+ struct timespec timeout;
+ timeout.tv_sec = 0;
+ timeout.tv_nsec = 5000;
+ return pselect (17, &set, NULL, NULL, &timeout, NULL) != -1 || errno != EBADF;
+]])], [gl_cv_func_pselect_detects_ebadf=yes],
+ [gl_cv_func_pselect_detects_ebadf=no],
+ [
+ case "$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
+])