1 files changed, 102 insertions, 0 deletions

diff --git a/gl/m4/sched_h.m4 b/gl/m4/sched_h.m4
new file mode 100644
index 00000000..1ffd465f
--- /dev/null
+++ b/gl/m4/sched_h.m4
@@ -0,0 +1,102 @@
+# sched_h.m4
+# serial 16
+dnl Copyright (C) 2008-2025 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.
+dnl This file is offered as-is, without any warranty.
+
+dnl Written by Bruno Haible.
+
+AC_DEFUN_ONCE([gl_SCHED_H],
+[
+  dnl Ensure to expand the default settings once only, before all statements
+  dnl that occur in other macros.
+  AC_REQUIRE([gl_SCHED_H_DEFAULTS])
+
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  AC_REQUIRE([gl_CHECK_HEADER_SYS_CDEFS_H])
+
+  AC_CHECK_HEADERS([sched.h], [], [],
+    [[#if HAVE_SYS_CDEFS_H
+       #include <sys/cdefs.h>
+      #endif
+    ]])
+  gl_NEXT_HEADERS([sched.h])
+
+  if test "$ac_cv_header_sched_h" = yes; then
+    HAVE_SCHED_H=1
+  else
+    HAVE_SCHED_H=0
+  fi
+  AC_SUBST([HAVE_SCHED_H])
+
+  if test "$HAVE_SCHED_H" = 1; then
+    AC_CHECK_TYPE([struct sched_param],
+      [HAVE_STRUCT_SCHED_PARAM=1], [HAVE_STRUCT_SCHED_PARAM=0],
+      [[#if HAVE_SYS_CDEFS_H
+         #include <sys/cdefs.h>
+        #endif
+        #include <sched.h>
+      ]])
+  else
+    HAVE_STRUCT_SCHED_PARAM=0
+    case "$host_os" in
+      os2*)
+        dnl On OS/2 kLIBC, struct sched_param is in spawn.h.
+        AC_CHECK_TYPE([struct sched_param],
+          [HAVE_STRUCT_SCHED_PARAM=1], [],
+          [#include <spawn.h>])
+        ;;
+      vms)
+        dnl On OpenVMS 7.2 or newer, struct sched_param is in pthread.h.
+        AC_CHECK_TYPE([struct sched_param],
+          [HAVE_STRUCT_SCHED_PARAM=1], [],
+          [#include <pthread.h>])
+        ;;
+    esac
+  fi
+  AC_SUBST([HAVE_STRUCT_SCHED_PARAM])
+
+  dnl Ensure the type pid_t gets defined.
+  AC_REQUIRE([AC_TYPE_PID_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, if it is not common
+  dnl enough to be declared everywhere.
+  gl_WARN_ON_USE_PREPARE([[#include <sched.h>
+    ]], [sched_yield])
+])
+
+# gl_SCHED_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
+AC_DEFUN([gl_SCHED_MODULE_INDICATOR],
+[
+  dnl Ensure to expand the default settings once only.
+  gl_SCHED_H_REQUIRE_DEFAULTS
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_SCHED_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_SCHED_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SCHED_YIELD])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_SCHED_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_SCHED_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_SCHED_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_SCHED_YIELD=1;    AC_SUBST([HAVE_SCHED_YIELD])
+  REPLACE_SCHED_YIELD=0; AC_SUBST([REPLACE_SCHED_YIELD])
+])