# lock.m4 serial 14

dnl Copyright (C) 2005-2020 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 From Bruno Haible.

AC_DEFUN([gl_LOCK],

[

  AC_REQUIRE([gl_THREADLIB])

  if test "$gl_threads_api" = posix; then

    # OSF/1 4.0 and Mac OS X 10.1 lack the pthread_rwlock_t type and the

    # pthread_rwlock_* functions.

    has_rwlock=false

    AC_CHECK_TYPE([pthread_rwlock_t],

      [has_rwlock=true

       AC_DEFINE([HAVE_PTHREAD_RWLOCK], [1],

         [Define if the POSIX multithreading library has read/write locks.])],

      [],

      [#include <pthread.h>])

    if $has_rwlock; then

      gl_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER

    fi

    # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.

    AC_COMPILE_IFELSE([

      AC_LANG_PROGRAM(

        [[#include <pthread.h>]],

        [[

#if __FreeBSD__ == 4

error "No, in FreeBSD 4.0 recursive mutexes actually don't work."

#elif (defined __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ \

       && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 1070)

error "No, in Mac OS X < 10.7 recursive mutexes actually don't work."

#else

int x = (int)PTHREAD_MUTEX_RECURSIVE;

return !x;

#endif

        ]])],

      [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], [1],

         [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])

  fi

  gl_PREREQ_LOCK

])

# Prerequisites of lib/glthread/lock.c.

AC_DEFUN([gl_PREREQ_LOCK], [:])