pthread_sigmask: Fix link requirements on OSF/1 5.1 and with pth.

[gnulib.git] / m4 / pthread_sigmask.m4

diff --git a/m4/pthread_sigmask.m4 b/m4/pthread_sigmask.m4
index 2147c08..984f69d 100644 (file)
--- a/m4/pthread_sigmask.m4
+++ b/m4/pthread_sigmask.m4
@@ -1,4 +1,4 @@
-# pthread_sigmask.m4 serial 4
+# pthread_sigmask.m4 serial 5
 dnl Copyright (C) 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,
@@ -6,21 +6,67 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_FUNC_PTHREAD_SIGMASK],
 [
+  AC_CHECK_FUNCS_ONCE([pthread_sigmask])
+  LIB_PTHREAD_SIGMASK=
   m4_ifdef([gl_THREADLIB], [
     AC_REQUIRE([gl_THREADLIB])
     if test "$gl_threads_api" = posix; then
-      gl_save_LIBS="$LIBS"
-      LIBS="$LIBS $LIBMULTITHREAD"
-      AC_CHECK_FUNCS([pthread_sigmask])
-      LIBS="$gl_save_LIBS"
+      if test $ac_cv_func_pthread_sigmask = yes; then
+        dnl pthread_sigmask is available without -lpthread.
+        :
+      else
+        if test -n "$LIBMULTITHREAD"; then
+          AC_CACHE_CHECK([for pthread_sigmask in $LIBMULTITHREAD],
+            [gl_cv_func_pthread_sigmask_in_LIBMULTITHREAD],
+            [gl_save_LIBS="$LIBS"
+             LIBS="$LIBS $LIBMULTITHREAD"
+             AC_COMPILE_IFELSE(
+               [AC_LANG_PROGRAM(
+                  [[#include <pthread.h>
+                    #include <signal.h>
+                  ]],
+                  [[return pthread_sigmask (0, (sigset_t *) 0, (sigset_t *) 0);]])
+               ],
+               [gl_cv_func_pthread_sigmask_in_LIBMULTITHREAD=yes],
+               [gl_cv_func_pthread_sigmask_in_LIBMULTITHREAD=no])
+             LIBS="$gl_save_LIBS"
+            ])
+          if test $gl_cv_func_pthread_sigmask_in_LIBMULTITHREAD = yes; then
+            dnl pthread_sigmask is available with -lpthread.
+            LIB_PTHREAD_SIGMASK="$LIBMULTITHREAD"
+          else
+            dnl pthread_sigmask is not available at all.
+            HAVE_PTHREAD_SIGMASK=0
+          fi
+        else
+          dnl pthread_sigmask is not available at all.
+          HAVE_PTHREAD_SIGMASK=0
+        fi
+      fi
     else
-      ac_cv_func_pthread_sigmask=no
+      dnl pthread_sigmask may exist but does not interoperate with the chosen
+      dnl multithreading facility.
+      dnl If "$gl_threads_api" = pth, we could use the function pth_sigmask,
+      dnl but it is equivalent to sigprocmask, so we choose to emulate
+      dnl pthread_sigmask with sigprocmask also in this case. This yields fewer
+      dnl link dependencies.
+      if test $ac_cv_func_pthread_sigmask = yes; then
+        REPLACE_PTHREAD_SIGMASK=1
+      else
+        HAVE_PTHREAD_SIGMASK=0
+      fi
+    fi
+  ] ,[
+    dnl If module 'threadlib' is not in use, assume all programs will be
+    dnl single-threaded.
+    if test $ac_cv_func_pthread_sigmask = yes; then
+      REPLACE_PTHREAD_SIGMASK=1
+    else
+      HAVE_PTHREAD_SIGMASK=0
     fi
-  ], [
-    AC_CHECK_FUNCS_ONCE([pthread_sigmask])
   ])
-
-  if test $ac_cv_func_pthread_sigmask = no; then
-    HAVE_PTHREAD_SIGMASK=0
-  fi
+  AC_SUBST([LIB_PTHREAD_SIGMASK])
+  dnl We don't need a variable LTLIB_PTHREAD_SIGMASK, because when
+  dnl "$gl_threads_api" = posix, $LTLIBMULTITHREAD and $LIBMULTITHREAD are the
+  dnl same: either both empty or both "-lpthread".
 ])