# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1315435739 -7200
# Node ID e6d5882454bce6e59052bfaff80404794f073d2a
# Parent  716e67b8d5a9cbc847824fdf28297a1e7d9eef3e
pthread: Determine $(LIB_PTHREAD) correctly on OSF/1 5.1.

* m4/pthread.m4 (gl_PTHREAD_CHECK): Use AC_CACHE_CHECK and
AC_LINK_IFELSE instead of AC_SEARCH_LIBS.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-09-07  Bruno Haible  <bruno@clisp.org>
+
+	pthread: Determine $(LIB_PTHREAD) correctly on OSF/1 5.1.
+	* m4/pthread.m4 (gl_PTHREAD_CHECK): Use AC_CACHE_CHECK and
+	AC_LINK_IFELSE instead of AC_SEARCH_LIBS.
+
 2011-09-07  Bruno Haible  <bruno@clisp.org>
 
 	openat: Work around compilation error with OSF/1 5.1 DTK cc.
diff --git a/m4/pthread.m4 b/m4/pthread.m4
--- a/m4/pthread.m4
+++ b/m4/pthread.m4
@@ -1,4 +1,4 @@
-# pthread.m4 serial 2
+# pthread.m4 serial 3
 dnl Copyright (C) 2009-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -38,12 +38,31 @@
 
    LIB_PTHREAD=
    if test $ac_cv_header_pthread_h = yes; then
-     gl_saved_libs=$LIBS
-     AC_SEARCH_LIBS([pthread_join], [pthread],
-       [if test "$ac_cv_search_pthread_join" != "none required"; then
-          LIB_PTHREAD="$ac_cv_search_pthread_join"
-        fi])
-     LIBS="$gl_saved_libs"
+     dnl We cannot use AC_SEARCH_LIBS here, because on OSF/1 5.1 pthread_join
+     dnl is defined as a macro which expands to __phread_join, and libpthread
+     dnl contains a definition for __phread_join but none for pthread_join.
+     AC_CACHE_CHECK([for library containing pthread_join],
+       [gl_cv_search_pthread_join],
+       [gl_saved_libs="$LIBS"
+        gl_cv_search_pthread_join=
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <pthread.h>]],
+             [[pthread_join (pthread_self (), (void **) 0);]])],
+          [gl_cv_search_pthread_join="none required"])
+        if test -z "$gl_cv_search_pthread_join"; then
+          LIBS="-lpthread $gl_saved_libs"
+          AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[#include <pthread.h>]],
+               [[pthread_join (pthread_self (), (void **) 0);]])],
+            [gl_cv_search_pthread_join="-lpthread"])
+        fi
+        LIBS="$gl_saved_libs"
+       ])
+     if test "$gl_cv_search_pthread_join" != "none required"; then
+       LIB_PTHREAD="$gl_cv_search_pthread_join"
+     fi
    fi
    AC_SUBST([LIB_PTHREAD])