On 06/13/2014 11:07 PM, Paul Eggert wrote:
> Pádraig Brady wrote:
>
>
>> + case "$host_os" in
>> + aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
>> + solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
>
> Why not use AC_DEFINE([_THREAD_SAFE], 1, ...) instead? That makes for
> shorter command lines in projects like Emacs. I don't see any advantage to
> putting it in CPPFLAGS.
Fair point. The reason that threadlib.m4 uses CPPFLAGS
is so that <pthread.h> is parseable on OSF/1.
But let's not try to cater for all old cases in the pthread module.
Also Bruno said that the existing pthread.h using code
in pthread.m4 works on (possibly newer) OSF/1:
http://lists.gnu.org/archive/html/bug-gnulib/2012-07/msg00106.html
So the attached patch is now completely independent of the threadlib module,
and uses AC_DEFINE.
I'll push later.
thanks,
Pádraig.
>From e671c501e95e9372db2f61a86aa27c986895c943 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <p...@draigbrady.com>
Date: Fri, 13 Jun 2014 19:56:20 +0100
Subject: [PATCH] pthread: define thread safe macros on some platforms
* m4/pthread.m4 (gl_PTHREAD_CHECK): Define macros needed
for thread safe access on some platforms.
---
ChangeLog | 6 ++++++
m4/pthread.m4 | 14 ++++++++++++++
2 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index cd19897..27fc247 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2014-06-14 Pádraig Brady <p...@draigbrady.com>
+
+ pthread: define thread safe macros on some platforms
+ * m4/pthread.m4 (gl_PTHREAD_CHECK): Define macros needed
+ for thread safe access on some platforms.
+
2014-06-13 Paul Eggert <egg...@cs.ucla.edu>
regex: don't be multithreaded if USE_UNLOCKED_IO.
diff --git a/m4/pthread.m4 b/m4/pthread.m4
index 1ed0dd3..cba1606 100644
--- a/m4/pthread.m4
+++ b/m4/pthread.m4
@@ -88,6 +88,20 @@ AC_DEFUN([gl_PTHREAD_CHECK],
fi
AC_SUBST([LIB_PTHREAD])
+ dnl Some systems optimize for single-threaded programs by default, and
+ dnl need special flags to disable these optimizations. For example, the
+ dnl definition of 'errno' in <errno.h>.
+ case "$host_os" in
+ aix* | freebsd*)
+ AC_DEFINE([_THREAD_SAFE], 1,
+ [Define on some systems, to enable only thread safe operations.])
+ ;;
+ osf* | solaris*)
+ AC_DEFINE([_REENTRANT], 1,
+ [Define on some systems, to enable only thread safe operations.])
+ ;;
+ esac
+
AC_REQUIRE([AC_C_RESTRICT])
])
--
1.7.7.6
