Edit
kc3-lang/libevent/m4/acx_pthread.m4
Niels Provos
- m4/acx_pthread.m4
-
##### http://autoconf-archive.cryp.to/acx_pthread.html # # SYNOPSIS # # ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) # # DESCRIPTION # # This macro figures out how to build C programs using POSIX threads. # It sets the PTHREAD_LIBS output variable to the threads library and # linker flags, and the PTHREAD_CFLAGS output variable to any special # C compiler flags that are needed. (The user can also force certain # compiler flags/libs to be tested by setting these environment # variables.) # # Also sets PTHREAD_CC to any special C compiler that is needed for # multi-threaded programs (defaults to the value of CC otherwise). # (This is necessary on AIX to use the special cc_r compiler alias.) # # NOTE: You are assumed to not only compile your program with these # flags, but also link it with them as well. e.g. you should link # with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS # $LIBS # # If you are only building threads programs, you may wish to use # these variables in your default LIBS, CFLAGS, and CC: # # LIBS="$PTHREAD_LIBS $LIBS" # CFLAGS="$CFLAGS $PTHREAD_CFLAGS" # CC="$PTHREAD_CC" # # In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute # constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to # that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). # # ACTION-IF-FOUND is a list of shell commands to run if a threads # library is found, and ACTION-IF-NOT-FOUND is a list of commands to # run it if it is not found. If ACTION-IF-FOUND is not specified, the # default action will define HAVE_PTHREAD. # # Please let the authors know if this macro fails on any platform, or # if you have any other suggestions or comments. This macro was based # on work by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) # (with help from M. Frigo), as well as ac_pthread and hb_pthread # macros posted by Alejandro Forero Cuervo to the autoconf macro # repository. We are also grateful for the helpful feedback of # numerous users. # # LAST MODIFICATION # # 2007-07-29 # # COPYLEFT # # Copyright (c) 2007 Steven G. Johnson <stevenj@alum.mit.edu> # # This program is free software: you can redistribute it and/or # modify it under the terms of the GNU General Public License as # published by the Free Software Foundation, either version 3 of the # License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see # <http://www.gnu.org/licenses/>. # # As a special exception, the respective Autoconf Macro's copyright # owner gives unlimited permission to copy, distribute and modify the # configure scripts that are the output of Autoconf when processing # the Macro. You need not follow the terms of the GNU General Public # License when using or distributing such scripts, even though # portions of the text of the Macro appear in them. The GNU General # Public License (GPL) does govern all other use of the material that # constitutes the Autoconf Macro. # # This special exception to the GPL applies to versions of the # Autoconf Macro released by the Autoconf Macro Archive. When you # make and distribute a modified version of the Autoconf Macro, you # may extend this special exception to the GPL to apply to your # modified version as well. AC_DEFUN([ACX_PTHREAD], [ AC_REQUIRE([AC_CANONICAL_HOST]) AC_LANG_SAVE AC_LANG_C acx_pthread_ok=no # We used to check for pthread.h first, but this fails if pthread.h # requires special compiler flags (e.g. on True64 or Sequent). # It gets checked for in the link test anyway. # First of all, check if the user has set any of the PTHREAD_LIBS, # etcetera environment variables, and if threads linking works using # them: if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then save_CFLAGS="$CFLAGS" CFLAGS="$CFLAGS $PTHREAD_CFLAGS" save_LIBS="$LIBS" LIBS="$PTHREAD_LIBS $LIBS" AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS]) AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes) AC_MSG_RESULT($acx_pthread_ok) if test x"$acx_pthread_ok" = xno; then PTHREAD_LIBS="" PTHREAD_CFLAGS="" fi LIBS="$save_LIBS" CFLAGS="$save_CFLAGS" fi # We must check for the threads library under a number of different # names; the ordering is very important because some systems # (e.g. DEC) have both -lpthread and -lpthreads, where one of the # libraries is broken (non-POSIX). # Create a list of thread flags to try. Items starting with a "-" are # C compiler flags, and other items are library names, except for "none" # which indicates that we try without any flags at all, and "pthread-config" # which is a program returning the flags for the Pth emulation library. acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" # The ordering *is* (sometimes) important. Some notes on the # individual items follow: # pthreads: AIX (must check this before -lpthread) # none: in case threads are in libc; should be tried before -Kthread and # other compiler flags to prevent continual compiler warnings # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads) # -pthreads: Solaris/gcc # -mthreads: Mingw32/gcc, Lynx/gcc # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it # doesn't hurt to check since this sometimes defines pthreads too; # also defines -D_REENTRANT) # ... -mt is also the pthreads flag for HP/aCC # pthread: Linux, etcetera # --thread-safe: KAI C++ # pthread-config: use pthread-config program (for GNU Pth library) case "${host_cpu}-${host_os}" in *solaris*) # On Solaris (at least, for some versions), libc contains stubbed # (non-functional) versions of the pthreads routines, so link-based # tests will erroneously succeed. (We need to link with -pthreads/-mt/ # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather # a function called by this macro, so we could check for that, but # who knows whether they'll stub that too in a future libc.) So, # we'll just look for -pthreads and -lpthread first: acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags" ;; esac if test x"$acx_pthread_ok" = xno; then for flag in $acx_pthread_flags; do case $flag in none) AC_MSG_CHECKING([whether pthreads work without any flags]) ;; -*) AC_MSG_CHECKING([whether pthreads work with $flag]) PTHREAD_CFLAGS="$flag" ;; pthread-config) AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no) if test x"$acx_pthread_config" = xno; then continue; fi PTHREAD_CFLAGS="`pthread-config --cflags`" PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" ;; *) AC_MSG_CHECKING([for the pthreads library -l$flag]) PTHREAD_LIBS="-l$flag" ;; esac save_LIBS="$LIBS" save_CFLAGS="$CFLAGS" LIBS="$PTHREAD_LIBS $LIBS" CFLAGS="$CFLAGS $PTHREAD_CFLAGS" # Check for various functions. We must include pthread.h, # since some functions may be macros. (On the Sequent, we # need a special flag -Kthread to make this header compile.) # We check for pthread_join because it is in -lpthread on IRIX # while pthread_create is in libc. We check for pthread_attr_init # due to DEC craziness with -lpthreads. We check for # pthread_cleanup_push because it is one of the few pthread # functions on Solaris that doesn't have a non-functional libc stub. # We try pthread_create on general principles. AC_TRY_LINK([#include <pthread.h>], [pthread_t th; pthread_join(th, 0); pthread_attr_init(0); pthread_cleanup_push(0, 0); pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], [acx_pthread_ok=yes]) LIBS="$save_LIBS" CFLAGS="$save_CFLAGS" AC_MSG_RESULT($acx_pthread_ok) if test "x$acx_pthread_ok" = xyes; then break; fi PTHREAD_LIBS="" PTHREAD_CFLAGS="" done fi # Various other checks: if test "x$acx_pthread_ok" = xyes; then save_LIBS="$LIBS" LIBS="$PTHREAD_LIBS $LIBS" save_CFLAGS="$CFLAGS" CFLAGS="$CFLAGS $PTHREAD_CFLAGS" # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. AC_MSG_CHECKING([for joinable pthread attribute]) attr_name=unknown for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;], [attr_name=$attr; break]) done AC_MSG_RESULT($attr_name) if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name, [Define to necessary symbol if this constant uses a non-standard name on your system.]) fi AC_MSG_CHECKING([if more special flags are required for pthreads]) flag=no case "${host_cpu}-${host_os}" in *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";; *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";; esac AC_MSG_RESULT(${flag}) if test "x$flag" != xno; then PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS" fi LIBS="$save_LIBS" CFLAGS="$save_CFLAGS" # More AIX lossage: must compile with xlc_r or cc_r if test x"$GCC" != xyes; then AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC}) else PTHREAD_CC=$CC fi else PTHREAD_CC="$CC" fi AC_SUBST(PTHREAD_LIBS) AC_SUBST(PTHREAD_CFLAGS) AC_SUBST(PTHREAD_CC) # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: if test x"$acx_pthread_ok" = xyes; then ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1]) : else acx_pthread_ok=no $2 fi AC_LANG_RESTORE ])dnl ACX_PTHREAD