-# threadlib.m4 serial 3 (gettext-0.18)
-dnl Copyright (C) 2005-2009 Free Software Foundation, Inc.
+# threadlib.m4 serial 8 (gettext-0.18.2)
+dnl Copyright (C) 2005-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl gl_THREADLIB
dnl ------------
dnl Tests for a multithreading library to be used.
+dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
+dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
+dnl default is 'no', otherwise it is system dependent. In both cases, the user
+dnl can change the choice through the options --enable-threads=choice or
+dnl --disable-threads.
dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
dnl USE_PTH_THREADS, USE_WIN32_THREADS
dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
[AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
[AC_REQUIRE([AC_GNU_SOURCE])])
dnl Check for multithreading.
- m4_divert_text([DEFAULTS], [gl_use_threads_default=])
+ m4_ifdef([gl_THREADLIB_DEFAULT_NO],
+ [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
+ [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
AC_ARG_ENABLE([threads],
-AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
-AC_HELP_STRING([--disable-threads], [build without multithread safety]),
+AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
+AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
[gl_use_threads=$enableval],
[if test -n "$gl_use_threads_default"; then
gl_use_threads="$gl_use_threads_default"
else
+changequote(,)dnl
case "$host_os" in
dnl Disable multithreading by default on OSF/1, because it interferes
dnl with fork()/exec(): When msgexec is linked with -lpthread, its
dnl child process gets an endless segmentation fault inside execvp().
+ dnl Disable multithreading by default on Cygwin 1.5.x, because it has
+ dnl bugs that lead to endless loops or crashes. See
+ dnl <http://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
osf*) gl_use_threads=no ;;
+ cygwin*)
+ case `uname -r` in
+ 1.[0-5].*) gl_use_threads=no ;;
+ *) gl_use_threads=yes ;;
+ esac
+ ;;
*) gl_use_threads=yes ;;
esac
+changequote([,])dnl
fi
])
if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
# groks <pthread.h>. cc also understands the flag -pthread, but
# we don't use it because 1. gcc-2.95 doesn't understand -pthread,
# 2. putting a flag into CPPFLAGS that has an effect on the linker
- # causes the AC_TRY_LINK test below to succeed unexpectedly,
+ # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
# leading to wrong values of LIBTHREAD and LTLIBTHREAD.
CPPFLAGS="$CPPFLAGS -D_REENTRANT"
;;
LTLIBMULTITHREAD=
if test "$gl_use_threads" != no; then
dnl Check whether the compiler and linker support weak declarations.
- AC_MSG_CHECKING([whether imported symbols can be declared weak])
- gl_have_weak=no
- AC_TRY_LINK([extern void xyzzy ();
-#pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes])
- AC_MSG_RESULT([$gl_have_weak])
+ AC_CACHE_CHECK([whether imported symbols can be declared weak],
+ [gl_cv_have_weak],
+ [gl_cv_have_weak=no
+ dnl First, test whether the compiler accepts it syntactically.
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[extern void xyzzy ();
+#pragma weak xyzzy]],
+ [[xyzzy();]])],
+ [gl_cv_have_weak=maybe])
+ if test $gl_cv_have_weak = maybe; then
+ dnl Second, test whether it actually works. On Cygwin 1.7.2, with
+ dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#include <stdio.h>
+#pragma weak fputs
+int main ()
+{
+ return (fputs == NULL);
+}]])],
+ [gl_cv_have_weak=yes],
+ [gl_cv_have_weak=no],
+ [dnl When cross-compiling, assume that only ELF platforms support
+ dnl weak symbols.
+ AC_EGREP_CPP([Extensible Linking Format],
+ [#ifdef __ELF__
+ Extensible Linking Format
+ #endif
+ ],
+ [gl_cv_have_weak="guessing yes"],
+ [gl_cv_have_weak="guessing no"])
+ ])
+ fi
+ ])
if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
# On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
# it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
# Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
# in libc. IRIX 6.5 has the first one in both libc and libpthread, but
# the second one only in libpthread, and lock.c needs it.
- AC_TRY_LINK([#include <pthread.h>],
- [pthread_mutex_lock((pthread_mutex_t*)0);
- pthread_mutexattr_init((pthread_mutexattr_t*)0);],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <pthread.h>]],
+ [[pthread_mutex_lock((pthread_mutex_t*)0);
+ pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
[gl_have_pthread=yes])
# Test for libpthread by looking for pthread_kill. (Not pthread_self,
# since it is defined as a macro on OSF/1.)
AC_DEFINE([USE_POSIX_THREADS], [1],
[Define if the POSIX multithreading library can be used.])
if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
- if test $gl_have_weak = yes; then
+ if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
[Define if references to the POSIX multithreading library should be made weak.])
LIBTHREAD=
gl_have_solaristhread=
gl_save_LIBS="$LIBS"
LIBS="$LIBS -lthread"
- AC_TRY_LINK([#include <thread.h>
-#include <synch.h>],
- [thr_self();],
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[
+#include <thread.h>
+#include <synch.h>
+ ]],
+ [[thr_self();]])],
[gl_have_solaristhread=yes])
LIBS="$gl_save_LIBS"
if test -n "$gl_have_solaristhread"; then
LTLIBMULTITHREAD="$LTLIBTHREAD"
AC_DEFINE([USE_SOLARIS_THREADS], [1],
[Define if the old Solaris multithreading library can be used.])
- if test $gl_have_weak = yes; then
+ if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
AC_DEFINE([USE_SOLARIS_THREADS_WEAK], [1],
[Define if references to the old Solaris multithreading library should be made weak.])
LIBTHREAD=
AC_LIB_LINKFLAGS([pth])
gl_have_pth=
gl_save_LIBS="$LIBS"
- LIBS="$LIBS -lpth"
- AC_TRY_LINK([#include <pth.h>], [pth_self();], [gl_have_pth=yes])
+ LIBS="$LIBS $LIBPTH"
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[#include <pth.h>]], [[pth_self();]])],
+ [gl_have_pth=yes])
LIBS="$gl_save_LIBS"
if test -n "$gl_have_pth"; then
gl_threads_api=pth
AC_DEFINE([USE_PTH_THREADS], [1],
[Define if the GNU Pth multithreading library can be used.])
if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
- if test $gl_have_weak = yes; then
+ if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
AC_DEFINE([USE_PTH_THREADS_WEAK], [1],
[Define if references to the GNU Pth multithreading library should be made weak.])
LIBTHREAD=