1 files changed, 73 insertions, 0 deletions
diff --git a/m4/pselect.m4 b/m4/pselect.m4
new file mode 100644
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
+])