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Diffstat (limited to 'm4/threadlib.m4')
| -rw-r--r-- | m4/threadlib.m4 | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4 new file mode 100644 index 0000000..ed6ebd5 --- /dev/null +++ b/m4/threadlib.m4 @@ -0,0 +1,473 @@ +# 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 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_WINDOWS_THREADS +dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use +dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with +dnl libtool). +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 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_DEFUN([gl_THREADLIB_EARLY], +[ + AC_REQUIRE([gl_THREADLIB_EARLY_BODY]) +]) + +dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once. + +AC_DEFUN([gl_THREADLIB_EARLY_BODY], +[ + dnl Ordering constraints: This macro modifies CPPFLAGS in a way that + dnl influences the result of the autoconf tests that test for *_unlocked + dnl declarations, on AIX 5 at least. Therefore it must come early. + AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl + AC_BEFORE([$0], [gl_ARGP])dnl + + AC_REQUIRE([AC_CANONICAL_HOST]) + dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems. + AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) + dnl Check for multithreading. + m4_ifdef([gl_THREADLIB_DEFAULT_NO], + [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])], + [m4_divert_text([DEFAULTS], [gl_use_threads_default=])]) + AC_ARG_ENABLE([threads], +AC_HELP_STRING([--enable-threads={posix|solaris|pth|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [ +AC_HELP_STRING([--disable-threads], [build without multithread safety])]), + [gl_use_threads=$enableval], + [if test -n "$gl_use_threads_default"; then + gl_use_threads="$gl_use_threads_default" + else +changequote(,)dnl + case "$host_os" in + dnl Disable multithreading by default on OSF/1, because it interferes + dnl with fork()/exec(): When msgexec is linked with -lpthread, its + dnl child process gets an endless segmentation fault inside execvp(). + dnl Disable multithreading by default on Cygwin 1.5.x, because it has + dnl bugs that lead to endless loops or crashes. See + dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>. + osf*) gl_use_threads=no ;; + cygwin*) + case `uname -r` in + 1.[0-5].*) gl_use_threads=no ;; + *) gl_use_threads=yes ;; + esac + ;; + *) gl_use_threads=yes ;; + esac +changequote([,])dnl + fi + ]) + if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then + # For using <pthread.h>: + case "$host_os" in + osf*) + # On OSF/1, the compiler needs the flag -D_REENTRANT so that it + # 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_LINK_IFELSE test below to succeed unexpectedly, + # leading to wrong values of LIBTHREAD and LTLIBTHREAD. + CPPFLAGS="$CPPFLAGS -D_REENTRANT" + ;; + esac + # Some systems optimize for single-threaded programs by default, and + # need special flags to disable these optimizations. For example, the + # definition of 'errno' in <errno.h>. + case "$host_os" in + aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;; + solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;; + esac + fi +]) + +dnl The guts of gl_THREADLIB. Needs to be expanded only once. + +AC_DEFUN([gl_THREADLIB_BODY], +[ + AC_REQUIRE([gl_THREADLIB_EARLY_BODY]) + gl_threads_api=none + LIBTHREAD= + LTLIBTHREAD= + LIBMULTITHREAD= + LTLIBMULTITHREAD= + if test "$gl_use_threads" != no; then + dnl Check whether the compiler and linker support weak declarations. + 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 + 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 "$gl_use_threads" = posix; then + # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that + # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY. + AC_CHECK_HEADER([pthread.h], + [gl_have_pthread_h=yes], [gl_have_pthread_h=no]) + if test "$gl_have_pthread_h" = yes; then + # Other possible tests: + # -lpthreads (FSU threads, PCthreads) + # -lgthreads + gl_have_pthread= + # 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. + # + # 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" && test -z "$LIBTHREAD"; then + # The program links fine without libpthread. But it may actually + # need to link with libpthread in order to create multiple threads. + AC_CHECK_LIB([pthread], [pthread_kill], + [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread + # On Solaris and HP-UX, most pthread functions exist also in libc. + # Therefore pthread_in_use() needs to actually try to create a + # thread: pthread_create from libc will fail, whereas + # pthread_create will actually create a thread. + # On Solaris 10 or newer, this test is no longer needed, because + # libc contains the fully functional pthread functions. + case "$host_os" in + solaris | 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 + ]) + elif test -z "$gl_have_pthread"; then + # Some library is needed. Try libpthread and libc_r. + AC_CHECK_LIB([pthread], [pthread_kill], + [gl_have_pthread=yes + LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread + LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread]) + if test -z "$gl_have_pthread"; then + # For FreeBSD 4. + AC_CHECK_LIB([c_r], [pthread_kill], + [gl_have_pthread=yes + LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r + LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r]) + fi + fi + if test -n "$gl_have_pthread"; then + gl_threads_api=posix + AC_DEFINE([USE_POSIX_THREADS], [1], + [Define if the POSIX multithreading library can be used.]) + if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then + if case "$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= + 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 $LIBMULTITHREAD" + fi + fi + ;; + esac + # TODO: May need to modify LTLIBMULTITHREAD similarly. + fi + fi + fi + fi + fi + if test -z "$gl_have_pthread"; then + if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then + gl_have_solaristhread= + gl_save_LIBS="$LIBS" + LIBS="$LIBS -lthread" + 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 + gl_threads_api=solaris + LIBTHREAD=-lthread + LTLIBTHREAD=-lthread + LIBMULTITHREAD="$LIBTHREAD" + LTLIBMULTITHREAD="$LTLIBTHREAD" + AC_DEFINE([USE_SOLARIS_THREADS], [1], + [Define if the old Solaris multithreading library can be used.]) + 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= + 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 $LIBMULTITHREAD" + fi + fi + # TODO: May need to modify LTLIBMULTITHREAD similarly. + fi + fi + fi + fi + if test "$gl_use_threads" = pth; then + gl_save_CPPFLAGS="$CPPFLAGS" + AC_LIB_LINKFLAGS([pth]) + gl_have_pth= + gl_save_LIBS="$LIBS" + 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 "$gl_have_pth"; then + gl_threads_api=pth + LIBTHREAD="$LIBPTH" + LTLIBTHREAD="$LTLIBPTH" + LIBMULTITHREAD="$LIBTHREAD" + LTLIBMULTITHREAD="$LTLIBTHREAD" + AC_DEFINE([USE_PTH_THREADS], [1], + [Define if the GNU Pth multithreading library can be used.]) + if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then + if case "$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= + 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 $LIBMULTITHREAD" + fi + fi + # TODO: May need to modify LTLIBMULTITHREAD similarly. + fi + fi + else + CPPFLAGS="$gl_save_CPPFLAGS" + fi + fi + if test -z "$gl_have_pthread"; then + case "$gl_use_threads" in + yes | windows | win32) # The 'win32' is for backward compatibility. + if { case "$host_os" in + mingw*) true;; + *) false;; + esac + }; then + gl_threads_api=windows + AC_DEFINE([USE_WINDOWS_THREADS], [1], + [Define if the native Windows multithreading API can be used.]) + fi + ;; + esac + fi + fi + AC_MSG_CHECKING([for multithread API to use]) + AC_MSG_RESULT([$gl_threads_api]) + AC_SUBST([LIBTHREAD]) + AC_SUBST([LTLIBTHREAD]) + AC_SUBST([LIBMULTITHREAD]) + AC_SUBST([LTLIBMULTITHREAD]) +]) + +AC_DEFUN([gl_THREADLIB], +[ + AC_REQUIRE([gl_THREADLIB_EARLY]) + AC_REQUIRE([gl_THREADLIB_BODY]) +]) + + +dnl gl_DISABLE_THREADS +dnl ------------------ +dnl Sets the gl_THREADLIB default so that threads are not used by default. +dnl The user can still override it at installation time, by using the +dnl configure option '--enable-threads'. + +AC_DEFUN([gl_DISABLE_THREADS], [ + m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no]) +]) + + +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 +dnl GNU Hurd/glibc posix +dnl +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 +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 +dnl NetBSD 1.6 -- +dnl +dnl OpenBSD 3.4 posix -lpthread Y OK +dnl +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 +dnl HP-UX 11 posix -lpthread N (cc) OK +dnl Y (gcc) +dnl +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 +dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK +dnl -lpthread (gcc) Y +dnl +dnl Cygwin posix -lpthread Y OK +dnl +dnl Any of the above pth -lpth 0.0 +dnl +dnl Mingw windows N OK +dnl +dnl BeOS 5 -- +dnl +dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is +dnl turned off: +dnl OK if all three tests terminate OK, +dnl 0.5 if the first test terminates OK but the second one loops endlessly, +dnl 0.0 if the first test already loops endlessly. |