cannam@147: # This file was copied to Cap'n Proto from the Protocol Buffers distribution,
cannam@147: # version 2.3.0.
cannam@147: 
cannam@147: # This was retrieved from
cannam@147: #    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?revision=1277&root=avahi
cannam@147: # See also (perhaps for new versions?)
cannam@147: #    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?root=avahi
cannam@147: #
cannam@147: # We've rewritten the inconsistency check code (from avahi), to work
cannam@147: # more broadly.  In particular, it no longer assumes ld accepts -zdefs.
cannam@147: # This caused a restructing of the code, but the functionality has only
cannam@147: # changed a little.
cannam@147: 
cannam@147: dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
cannam@147: dnl
cannam@147: dnl @summary figure out how to build C programs using POSIX threads
cannam@147: dnl
cannam@147: dnl This macro figures out how to build C programs using POSIX threads.
cannam@147: dnl It sets the PTHREAD_LIBS output variable to the threads library and
cannam@147: dnl linker flags, and the PTHREAD_CFLAGS output variable to any special
cannam@147: dnl C compiler flags that are needed. (The user can also force certain
cannam@147: dnl compiler flags/libs to be tested by setting these environment
cannam@147: dnl variables.)
cannam@147: dnl
cannam@147: dnl Also sets PTHREAD_CC to any special C compiler that is needed for
cannam@147: dnl multi-threaded programs (defaults to the value of CC otherwise).
cannam@147: dnl (This is necessary on AIX to use the special cc_r compiler alias.)
cannam@147: dnl
cannam@147: dnl NOTE: You are assumed to not only compile your program with these
cannam@147: dnl flags, but also link it with them as well. e.g. you should link
cannam@147: dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS
cannam@147: dnl $LIBS
cannam@147: dnl
cannam@147: dnl If you are only building threads programs, you may wish to use
cannam@147: dnl these variables in your default LIBS, CFLAGS, and CC:
cannam@147: dnl
cannam@147: dnl        LIBS="$PTHREAD_LIBS $LIBS"
cannam@147: dnl        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@147: dnl        CC="$PTHREAD_CC"
cannam@147: dnl
cannam@147: dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
cannam@147: dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
cannam@147: dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
cannam@147: dnl
cannam@147: dnl ACTION-IF-FOUND is a list of shell commands to run if a threads
cannam@147: dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to
cannam@147: dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the
cannam@147: dnl default action will define HAVE_PTHREAD.
cannam@147: dnl
cannam@147: dnl Please let the authors know if this macro fails on any platform, or
cannam@147: dnl if you have any other suggestions or comments. This macro was based
cannam@147: dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with
cannam@147: dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros
cannam@147: dnl posted by Alejandro Forero Cuervo to the autoconf macro repository.
cannam@147: dnl We are also grateful for the helpful feedback of numerous users.
cannam@147: dnl
cannam@147: dnl @category InstalledPackages
cannam@147: dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
cannam@147: dnl @version 2006-05-29
cannam@147: dnl @license GPLWithACException
cannam@147: dnl
cannam@147: dnl Checks for GCC shared/pthread inconsistency based on work by
cannam@147: dnl Marcin Owsiany <marcin@owsiany.pl>
cannam@147: 
cannam@147: 
cannam@147: AC_DEFUN([ACX_PTHREAD], [
cannam@147: AC_REQUIRE([AC_CANONICAL_HOST])
cannam@147: AC_LANG_SAVE
cannam@147: AC_LANG_C
cannam@147: acx_pthread_ok=no
cannam@147: 
cannam@147: # We used to check for pthread.h first, but this fails if pthread.h
cannam@147: # requires special compiler flags (e.g. on True64 or Sequent).
cannam@147: # It gets checked for in the link test anyway.
cannam@147: 
cannam@147: # First of all, check if the user has set any of the PTHREAD_LIBS,
cannam@147: # etcetera environment variables, and if threads linking works using
cannam@147: # them:
cannam@147: if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
cannam@147:         save_CFLAGS="$CFLAGS"
cannam@147:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@147:         save_LIBS="$LIBS"
cannam@147:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@147:         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
cannam@147:         AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
cannam@147:         AC_MSG_RESULT($acx_pthread_ok)
cannam@147:         if test x"$acx_pthread_ok" = xno; then
cannam@147:                 PTHREAD_LIBS=""
cannam@147:                 PTHREAD_CFLAGS=""
cannam@147:         fi
cannam@147:         LIBS="$save_LIBS"
cannam@147:         CFLAGS="$save_CFLAGS"
cannam@147: fi
cannam@147: 
cannam@147: # We must check for the threads library under a number of different
cannam@147: # names; the ordering is very important because some systems
cannam@147: # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
cannam@147: # libraries is broken (non-POSIX).
cannam@147: 
cannam@147: # Create a list of thread flags to try.  Items starting with a "-" are
cannam@147: # C compiler flags, and other items are library names, except for "none"
cannam@147: # which indicates that we try without any flags at all, and "pthread-config"
cannam@147: # which is a program returning the flags for the Pth emulation library.
cannam@147: 
cannam@147: acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
cannam@147: 
cannam@147: # The ordering *is* (sometimes) important.  Some notes on the
cannam@147: # individual items follow:
cannam@147: 
cannam@147: # pthreads: AIX (must check this before -lpthread)
cannam@147: # none: in case threads are in libc; should be tried before -Kthread and
cannam@147: #       other compiler flags to prevent continual compiler warnings
cannam@147: # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
cannam@147: # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
cannam@147: # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
cannam@147: # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
cannam@147: # -pthreads: Solaris/gcc
cannam@147: # -mthreads: Mingw32/gcc, Lynx/gcc
cannam@147: # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
cannam@147: #      doesn't hurt to check since this sometimes defines pthreads too;
cannam@147: #      also defines -D_REENTRANT)
cannam@147: #      ... -mt is also the pthreads flag for HP/aCC
cannam@147: # pthread: Linux, etcetera
cannam@147: # --thread-safe: KAI C++
cannam@147: # pthread-config: use pthread-config program (for GNU Pth library)
cannam@147: 
cannam@147: case "${host_cpu}-${host_os}" in
cannam@147:         *solaris*)
cannam@147: 
cannam@147:         # On Solaris (at least, for some versions), libc contains stubbed
cannam@147:         # (non-functional) versions of the pthreads routines, so link-based
cannam@147:         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
cannam@147:         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
cannam@147:         # a function called by this macro, so we could check for that, but
cannam@147:         # who knows whether they'll stub that too in a future libc.)  So,
cannam@147:         # we'll just look for -pthreads and -lpthread first:
cannam@147: 
cannam@147:         acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
cannam@147:         ;;
cannam@147: esac
cannam@147: 
cannam@147: if test x"$acx_pthread_ok" = xno; then
cannam@147: for flag in $acx_pthread_flags; do
cannam@147: 
cannam@147:         case $flag in
cannam@147:                 none)
cannam@147:                 AC_MSG_CHECKING([whether pthreads work without any flags])
cannam@147:                 ;;
cannam@147: 
cannam@147:                 -*)
cannam@147:                 AC_MSG_CHECKING([whether pthreads work with $flag])
cannam@147:                 PTHREAD_CFLAGS="$flag"
cannam@147:                 ;;
cannam@147: 
cannam@147: 		pthread-config)
cannam@147: 		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
cannam@147: 		if test x"$acx_pthread_config" = xno; then continue; fi
cannam@147: 		PTHREAD_CFLAGS="`pthread-config --cflags`"
cannam@147: 		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
cannam@147: 		;;
cannam@147: 
cannam@147:                 *)
cannam@147:                 AC_MSG_CHECKING([for the pthreads library -l$flag])
cannam@147:                 PTHREAD_LIBS="-l$flag"
cannam@147:                 ;;
cannam@147:         esac
cannam@147: 
cannam@147:         save_LIBS="$LIBS"
cannam@147:         save_CFLAGS="$CFLAGS"
cannam@147:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@147:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@147: 
cannam@147:         # Check for various functions.  We must include pthread.h,
cannam@147:         # since some functions may be macros.  (On the Sequent, we
cannam@147:         # need a special flag -Kthread to make this header compile.)
cannam@147:         # We check for pthread_join because it is in -lpthread on IRIX
cannam@147:         # while pthread_create is in libc.  We check for pthread_attr_init
cannam@147:         # due to DEC craziness with -lpthreads.  We check for
cannam@147:         # pthread_cleanup_push because it is one of the few pthread
cannam@147:         # functions on Solaris that doesn't have a non-functional libc stub.
cannam@147:         # We try pthread_create on general principles.
cannam@147:         AC_TRY_LINK([#include <pthread.h>],
cannam@147:                     [pthread_t th; pthread_join(th, 0);
cannam@147:                      pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147:                      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147:                     [acx_pthread_ok=yes])
cannam@147: 
cannam@147:         LIBS="$save_LIBS"
cannam@147:         CFLAGS="$save_CFLAGS"
cannam@147: 
cannam@147:         AC_MSG_RESULT($acx_pthread_ok)
cannam@147:         if test "x$acx_pthread_ok" = xyes; then
cannam@147:                 break;
cannam@147:         fi
cannam@147: 
cannam@147:         PTHREAD_LIBS=""
cannam@147:         PTHREAD_CFLAGS=""
cannam@147: done
cannam@147: fi
cannam@147: 
cannam@147: # Various other checks:
cannam@147: if test "x$acx_pthread_ok" = xyes; then
cannam@147:         save_LIBS="$LIBS"
cannam@147:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@147:         save_CFLAGS="$CFLAGS"
cannam@147:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@147: 
cannam@147:         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
cannam@147: 	AC_MSG_CHECKING([for joinable pthread attribute])
cannam@147: 	attr_name=unknown
cannam@147: 	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
cannam@147: 	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
cannam@147:                         [attr_name=$attr; break])
cannam@147: 	done
cannam@147:         AC_MSG_RESULT($attr_name)
cannam@147:         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
cannam@147:             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
cannam@147:                                [Define to necessary symbol if this constant
cannam@147:                                 uses a non-standard name on your system.])
cannam@147:         fi
cannam@147: 
cannam@147:         AC_MSG_CHECKING([if more special flags are required for pthreads])
cannam@147:         flag=no
cannam@147:         case "${host_cpu}-${host_os}" in
cannam@147:             *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
cannam@147:             *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
cannam@147:         esac
cannam@147:         AC_MSG_RESULT(${flag})
cannam@147:         if test "x$flag" != xno; then
cannam@147:             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
cannam@147:         fi
cannam@147: 
cannam@147:         LIBS="$save_LIBS"
cannam@147:         CFLAGS="$save_CFLAGS"
cannam@147:         # More AIX lossage: must compile with xlc_r or cc_r
cannam@147: 	if test x"$GCC" != xyes; then
cannam@147:           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
cannam@147:         else
cannam@147:           PTHREAD_CC=$CC
cannam@147: 	fi
cannam@147: 
cannam@147: 	# The next part tries to detect GCC inconsistency with -shared on some
cannam@147: 	# architectures and systems. The problem is that in certain
cannam@147: 	# configurations, when -shared is specified, GCC "forgets" to
cannam@147: 	# internally use various flags which are still necessary.
cannam@147: 
cannam@147: 	#
cannam@147: 	# Prepare the flags
cannam@147: 	#
cannam@147: 	save_CFLAGS="$CFLAGS"
cannam@147: 	save_LIBS="$LIBS"
cannam@147: 	save_CC="$CC"
cannam@147: 
cannam@147: 	# Try with the flags determined by the earlier checks.
cannam@147: 	#
cannam@147: 	# -Wl,-z,defs forces link-time symbol resolution, so that the
cannam@147: 	# linking checks with -shared actually have any value
cannam@147: 	#
cannam@147: 	# FIXME: -fPIC is required for -shared on many architectures,
cannam@147: 	# so we specify it here, but the right way would probably be to
cannam@147: 	# properly detect whether it is actually required.
cannam@147: 	CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS"
cannam@147: 	LIBS="$PTHREAD_LIBS $LIBS"
cannam@147: 	CC="$PTHREAD_CC"
cannam@147: 
cannam@147: 	# In order not to create several levels of indentation, we test
cannam@147: 	# the value of "$done" until we find the cure or run out of ideas.
cannam@147: 	done="no"
cannam@147: 
cannam@147: 	# First, make sure the CFLAGS we added are actually accepted by our
cannam@147: 	# compiler.  If not (and OS X's ld, for instance, does not accept -z),
cannam@147: 	# then we can't do this test.
cannam@147: 	if test x"$done" = xno; then
cannam@147: 	   AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])
cannam@147: 	   AC_TRY_LINK(,, , [done=yes])
cannam@147: 
cannam@147: 	   if test "x$done" = xyes ; then
cannam@147: 	      AC_MSG_RESULT([no])
cannam@147: 	   else
cannam@147: 	      AC_MSG_RESULT([yes])
cannam@147: 	   fi
cannam@147: 	fi
cannam@147: 
cannam@147: 	if test x"$done" = xno; then
cannam@147: 	   AC_MSG_CHECKING([whether -pthread is sufficient with -shared])
cannam@147: 	   AC_TRY_LINK([#include <pthread.h>],
cannam@147: 	      [pthread_t th; pthread_join(th, 0);
cannam@147: 	      pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147: 	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147: 	      [done=yes])
cannam@147: 
cannam@147: 	   if test "x$done" = xyes; then
cannam@147: 	      AC_MSG_RESULT([yes])
cannam@147: 	   else
cannam@147: 	      AC_MSG_RESULT([no])
cannam@147: 	   fi
cannam@147: 	fi
cannam@147: 
cannam@147: 	#
cannam@147: 	# Linux gcc on some architectures such as mips/mipsel forgets
cannam@147: 	# about -lpthread
cannam@147: 	#
cannam@147: 	if test x"$done" = xno; then
cannam@147: 	   AC_MSG_CHECKING([whether -lpthread fixes that])
cannam@147: 	   LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"
cannam@147: 	   AC_TRY_LINK([#include <pthread.h>],
cannam@147: 	      [pthread_t th; pthread_join(th, 0);
cannam@147: 	      pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147: 	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147: 	      [done=yes])
cannam@147: 
cannam@147: 	   if test "x$done" = xyes; then
cannam@147: 	      AC_MSG_RESULT([yes])
cannam@147: 	      PTHREAD_LIBS="-lpthread $PTHREAD_LIBS"
cannam@147: 	   else
cannam@147: 	      AC_MSG_RESULT([no])
cannam@147: 	   fi
cannam@147: 	fi
cannam@147: 	#
cannam@147: 	# FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc
cannam@147: 	#
cannam@147: 	if test x"$done" = xno; then
cannam@147: 	   AC_MSG_CHECKING([whether -lc_r fixes that])
cannam@147: 	   LIBS="-lc_r $PTHREAD_LIBS $save_LIBS"
cannam@147: 	   AC_TRY_LINK([#include <pthread.h>],
cannam@147: 	       [pthread_t th; pthread_join(th, 0);
cannam@147: 	        pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147: 	        pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147: 	       [done=yes])
cannam@147: 
cannam@147: 	   if test "x$done" = xyes; then
cannam@147: 	      AC_MSG_RESULT([yes])
cannam@147: 	      PTHREAD_LIBS="-lc_r $PTHREAD_LIBS"
cannam@147: 	   else
cannam@147: 	      AC_MSG_RESULT([no])
cannam@147: 	   fi
cannam@147: 	fi
cannam@147: 	if test x"$done" = xno; then
cannam@147: 	   # OK, we have run out of ideas
cannam@147: 	   AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries])
cannam@147: 
cannam@147: 	   # so it's not safe to assume that we may use pthreads
cannam@147: 	   acx_pthread_ok=no
cannam@147: 	fi
cannam@147: 
cannam@147:         CFLAGS="$save_CFLAGS"
cannam@147:         LIBS="$save_LIBS"
cannam@147:         CC="$save_CC"
cannam@147: else
cannam@147:         PTHREAD_CC="$CC"
cannam@147: fi
cannam@147: 
cannam@147: if test "x$acx_pthread_ok" = xyes; then
cannam@147:         # One more check: If we chose to use a compiler flag like -pthread but it is combined with
cannam@147:         # -nostdlib then the compiler won't implicitly link against libpthread. This can happen
cannam@147:         # in particular when using some versions of libtool on some distros. See:
cannam@147:         #     https://bugzilla.redhat.com/show_bug.cgi?id=661333
cannam@147: 
cannam@147:         save_CFLAGS="$CFLAGS"
cannam@147:         save_LIBS="$LIBS"
cannam@147:         save_CC="$CC"
cannam@147:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@147:         LIBS="-nostdlib $PTHREAD_LIBS $LIBS -lc"
cannam@147:         CC="$PTHREAD_CC"
cannam@147: 
cannam@147:         AC_MSG_CHECKING([whether pthread flag is sufficient with -nostdlib])
cannam@147:         AC_TRY_LINK([#include <pthread.h>],
cannam@147:                     [pthread_t th; pthread_join(th, 0);
cannam@147:                      pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147:                      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147:                     [AC_MSG_RESULT([yes])], [
cannam@147:           AC_MSG_RESULT([no])
cannam@147: 
cannam@147:           AC_MSG_CHECKING([whether adding -lpthread fixes that])
cannam@147: 
cannam@147:           LIBS="-nostdlib $PTHREAD_LIBS -lpthread $save_LIBS -lc"
cannam@147:           AC_TRY_LINK([#include <pthread.h>],
cannam@147:                       [pthread_t th; pthread_join(th, 0);
cannam@147:                        pthread_attr_init(0); pthread_cleanup_push(0, 0);
cannam@147:                        pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
cannam@147:                       [
cannam@147:             AC_MSG_RESULT([yes])
cannam@147:             PTHREAD_LIBS="$PTHREAD_LIBS -lpthread"
cannam@147:           ], [AC_MSG_RESULT([no])])
cannam@147:         ])
cannam@147: 
cannam@147:         CFLAGS="$save_CFLAGS"
cannam@147:         LIBS="$save_LIBS"
cannam@147:         CC="$save_CC"
cannam@147: fi
cannam@147: 
cannam@147: AC_SUBST(PTHREAD_LIBS)
cannam@147: AC_SUBST(PTHREAD_CFLAGS)
cannam@147: AC_SUBST(PTHREAD_CC)
cannam@147: 
cannam@147: # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
cannam@147: if test x"$acx_pthread_ok" = xyes; then
cannam@147:         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
cannam@147:         :
cannam@147: else
cannam@147:         acx_pthread_ok=no
cannam@147:         $2
cannam@147: fi
cannam@147: AC_LANG_RESTORE
cannam@147: ])dnl ACX_PTHREAD