1# lock.m4 serial 14
2dnl Copyright (C) 2005-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Bruno Haible.
8
9AC_DEFUN([gl_LOCK],
10[
11  AC_REQUIRE([gl_THREADLIB])
12  if test "$gl_threads_api" = posix; then
13    # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the
14    # pthread_rwlock_* functions.
15    has_rwlock=false
16    AC_CHECK_TYPE([pthread_rwlock_t],
17      [has_rwlock=true
18       AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],
19         [Define if the POSIX multithreading library has read/write locks.])],
20      [],
21      [#include <pthread.h>])
22    if $has_rwlock; then
23      gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
24    fi
25    # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
26    AC_COMPILE_IFELSE([
27      AC_LANG_PROGRAM(
28        [[#include <pthread.h>]],
29        [[
30#if __FreeBSD__ == 4
31error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
32#elif (defined __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ \
33       && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1070)
34error "No, in Mac OS X < 10.7 recursive mutexes actually don't work."
35#else
36int x = (int)PTHREAD_MUTEX_RECURSIVE;
37return !x;
38#endif
39        ]])],
40      [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], [1],
41         [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
42  fi
43  gl_PREREQ_LOCK
44])
45
46# Prerequisites of lib/glthread/lock.c.
47AC_DEFUN([gl_PREREQ_LOCK], [:])
48