-# threadlib.m4 serial 9 (gettext-0.18.2)
-dnl Copyright (C) 2005-2012 Free Software Foundation, Inc.
+# threadlib.m4 serial 15
+dnl Copyright (C) 2005-2018 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_PREREQ([2.60])
+
dnl gl_THREADLIB
dnl ------------
dnl Tests for a multithreading library to be used.
dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
dnl programs that really need multithread functionality. The difference
dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
-dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
+dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
dnl multithread-safe programs.
AC_REQUIRE([AC_CANONICAL_HOST])
dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
- dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
- dnl AC_GNU_SOURCE.
- m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
- [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
- [AC_REQUIRE([AC_GNU_SOURCE])])
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
dnl Check for multithreading.
m4_ifdef([gl_THREADLIB_DEFAULT_NO],
[m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
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>.
+ dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
osf*) gl_use_threads=no ;;
cygwin*)
case `uname -r` in
[gl_cv_have_weak="guessing no"])
])
fi
+ dnl But when linking statically, weak symbols don't work.
+ case " $LDFLAGS " in
+ *" -static "*) gl_cv_have_weak=no ;;
+ esac
+ ])
+ dnl Check whether the linker supports the --as-needed/--no-as-needed options.
+ dnl Assume GCC, so that we can use the -Wl option.
+ AC_CACHE_CHECK([whether the linker supports --as-needed],
+ [gl_cv_linker_have_as_needed],
+ [if test -n "$GCC"; then
+ gl_saved_ldflags="$LDFLAGS"
+ LDFLAGS="$gl_saved_ldflags -Wl,--as-needed -Wl,--no-as-needed"
+ AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+ [gl_cv_linker_have_as_needed=yes],
+ [gl_cv_linker_have_as_needed=no])
+ LDFLAGS="$gl_saved_ldflags"
+ else
+ gl_cv_linker_have_as_needed=no
+ fi
+ ])
+ dnl Check whether the linker supports the --push-state/--pop-state options.
+ dnl Assume GCC, so that we can use the -Wl option.
+ AC_CACHE_CHECK([whether the linker supports --push-state],
+ [gl_cv_linker_have_push_state],
+ [if test -n "$GCC"; then
+ gl_saved_ldflags="$LDFLAGS"
+ LDFLAGS="$gl_saved_ldflags -Wl,--push-state -Wl,--pop-state"
+ AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+ [gl_cv_linker_have_push_state=yes],
+ [gl_cv_linker_have_push_state=no])
+ LDFLAGS="$gl_saved_ldflags"
+ else
+ gl_cv_linker_have_push_state=no
+ fi
])
if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
# On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
# Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
# in libc. IRIX 6.5 has the first one in both libc and libpthread, but
# the second one only in libpthread, and lock.c needs it.
- AC_LINK_IFELSE(
- [AC_LANG_PROGRAM(
- [[#include <pthread.h>]],
- [[pthread_mutex_lock((pthread_mutex_t*)0);
- pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
- [gl_have_pthread=yes])
+ #
+ # If -pthread works, prefer it to -lpthread, since Ubuntu 14.04
+ # needs -pthread for some reason. See:
+ # https://lists.gnu.org/r/bug-gnulib/2014-09/msg00023.html
+ save_LIBS=$LIBS
+ for gl_pthread in '' '-pthread'; do
+ LIBS="$LIBS $gl_pthread"
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <pthread.h>
+ pthread_mutex_t m;
+ pthread_mutexattr_t ma;
+ ]],
+ [[pthread_mutex_lock (&m);
+ pthread_mutexattr_init (&ma);]])],
+ [gl_have_pthread=yes
+ LIBTHREAD=$gl_pthread LTLIBTHREAD=$gl_pthread
+ LIBMULTITHREAD=$gl_pthread LTLIBMULTITHREAD=$gl_pthread])
+ LIBS=$save_LIBS
+ test -n "$gl_have_pthread" && break
+ done
+
# Test for libpthread by looking for pthread_kill. (Not pthread_self,
# since it is defined as a macro on OSF/1.)
- if test -n "$gl_have_pthread"; then
+ if test -n "$gl_have_pthread" && test -z "$LIBTHREAD"; then
# The program links fine without libpthread. But it may actually
# need to link with libpthread in order to create multiple threads.
AC_CHECK_LIB([pthread], [pthread_kill],
# Therefore pthread_in_use() needs to actually try to create a
# thread: pthread_create from libc will fail, whereas
# pthread_create will actually create a thread.
+ # On Solaris 10 or newer, this test is no longer needed, because
+ # libc contains the fully functional pthread functions.
case "$host_os" in
- solaris* | hpux*)
+ solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*)
AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
[Define if the pthread_in_use() detection is hard.])
esac
])
- else
+ elif test -z "$gl_have_pthread"; then
# Some library is needed. Try libpthread and libc_r.
AC_CHECK_LIB([pthread], [pthread_kill],
[gl_have_pthread=yes
[Define if references to the POSIX multithreading library should be made weak.])
LIBTHREAD=
LTLIBTHREAD=
+ dnl On platforms where GCC enables --as-needed by default, attempt
+ dnl to make sure that LIBMULTITHREAD really links with -lpthread.
+ dnl Otherwise linking with LIBMULTITHREAD has no effect; then
+ dnl the weak symbols are not defined and thus evaluate to NULL.
+ case "$LIBMULTITHREAD" in
+ "") ;;
+ -pthread)
+ if test $gl_cv_linker_have_as_needed = yes; then
+ if test $gl_cv_linker_have_push_state = yes; then
+ LIBMULTITHREAD="$LIBMULTITHREAD -Wl,--push-state -Wl,--no-as-needed -lpthread -Wl,--pop-state"
+ else
+ LIBMULTITHREAD="$LIBMULTITHREAD -Wl,--no-as-needed -lpthread"
+ fi
+ fi
+ ;;
+ *)
+ if test $gl_cv_linker_have_as_needed = yes; then
+ if test $gl_cv_linker_have_push_state = yes; then
+ LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state"
+ else
+ LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD"
+ fi
+ fi
+ ;;
+ esac
+ # TODO: May need to modify LTLIBMULTITHREAD similarly.
fi
fi
fi
[Define if references to the old Solaris multithreading library should be made weak.])
LIBTHREAD=
LTLIBTHREAD=
+ dnl On platforms where GCC enables --as-needed by default, attempt
+ dnl to make sure that LIBMULTITHREAD really links with -lthread.
+ dnl Otherwise linking with LIBMULTITHREAD has no effect; then
+ dnl the weak symbols are not defined and thus evaluate to NULL.
+ if test $gl_cv_linker_have_as_needed = yes; then
+ if test $gl_cv_linker_have_push_state = yes; then
+ LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state"
+ else
+ LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD"
+ fi
+ fi
+ # TODO: May need to modify LTLIBMULTITHREAD similarly.
fi
fi
fi
[Define if references to the GNU Pth multithreading library should be made weak.])
LIBTHREAD=
LTLIBTHREAD=
+ dnl On platforms where GCC enables --as-needed by default, attempt
+ dnl to make sure that LIBMULTITHREAD really links with -lpth.
+ dnl Otherwise linking with LIBMULTITHREAD has no effect; then
+ dnl the weak symbols are not defined and thus evaluate to NULL.
+ if test $gl_cv_linker_have_as_needed = yes; then
+ if test $gl_cv_linker_have_push_state = yes; then
+ LIBMULTITHREAD="-Wl,--push-state -Wl,--no-as-needed $LIBMULTITHREAD -Wl,--pop-state"
+ else
+ LIBMULTITHREAD="-Wl,--no-as-needed $LIBMULTITHREAD"
+ fi
+ fi
+ # TODO: May need to modify LTLIBMULTITHREAD similarly.
fi
fi
else
dnl Survey of platforms:
dnl
-dnl Platform Available Compiler Supports test-lock
-dnl flavours option weak result
-dnl --------------- --------- --------- -------- ---------
-dnl Linux 2.4/glibc posix -lpthread Y OK
+dnl Platform Available Compiler Supports test-lock
+dnl flavours option weak result
+dnl --------------- --------- --------- -------- ---------
+dnl Linux 2.4/glibc posix -lpthread Y OK
+dnl
+dnl GNU Hurd/glibc posix
dnl
-dnl GNU Hurd/glibc posix
+dnl Ubuntu 14.04 posix -pthread Y OK
dnl
-dnl FreeBSD 5.3 posix -lc_r Y
-dnl posix -lkse ? Y
-dnl posix -lpthread ? Y
-dnl posix -lthr Y
+dnl FreeBSD 5.3 posix -lc_r Y
+dnl posix -lkse ? Y
+dnl posix -lpthread ? Y
+dnl posix -lthr Y
dnl
-dnl FreeBSD 5.2 posix -lc_r Y
-dnl posix -lkse Y
-dnl posix -lthr Y
+dnl FreeBSD 5.2 posix -lc_r Y
+dnl posix -lkse Y
+dnl posix -lthr Y
dnl
-dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
+dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
dnl
-dnl NetBSD 1.6 --
+dnl NetBSD 1.6 --
dnl
-dnl OpenBSD 3.4 posix -lpthread Y OK
+dnl OpenBSD 3.4 posix -lpthread Y OK
dnl
-dnl MacOS X 10.[123] posix -lpthread Y OK
+dnl Mac OS X 10.[123] posix -lpthread Y OK
dnl
-dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
-dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
+dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
+dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
dnl
-dnl HP-UX 11 posix -lpthread N (cc) OK
+dnl HP-UX 11 posix -lpthread N (cc) OK
dnl Y (gcc)
dnl
-dnl IRIX 6.5 posix -lpthread Y 0.5
+dnl IRIX 6.5 posix -lpthread Y 0.5
dnl
-dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
+dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
dnl
-dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
+dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
dnl -lpthread (gcc) Y
dnl
-dnl Cygwin posix -lpthread Y OK
+dnl Cygwin posix -lpthread Y OK
dnl
-dnl Any of the above pth -lpth 0.0
+dnl Any of the above pth -lpth 0.0
dnl
-dnl Mingw windows N OK
+dnl Mingw windows N OK
dnl
-dnl BeOS 5 --
+dnl BeOS 5 --
dnl
dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
dnl turned off:
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