cannam@167: dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
cannam@167: dnl @summary figure out how to build C programs using POSIX threads
cannam@167: dnl @category InstalledPackages
cannam@167: dnl
cannam@167: dnl This macro figures out how to build C programs using POSIX
cannam@167: dnl threads.  It sets the PTHREAD_LIBS output variable to the threads
cannam@167: dnl library and linker flags, and the PTHREAD_CFLAGS output variable
cannam@167: dnl to any special C compiler flags that are needed.  (The user can also
cannam@167: dnl force certain compiler flags/libs to be tested by setting these
cannam@167: dnl environment variables.)
cannam@167: dnl
cannam@167: dnl Also sets PTHREAD_CC to any special C compiler that is needed for
cannam@167: dnl multi-threaded programs (defaults to the value of CC otherwise).
cannam@167: dnl (This is necessary on AIX to use the special cc_r compiler alias.)
cannam@167: dnl
cannam@167: dnl NOTE: You are assumed to not only compile your program with these
cannam@167: dnl flags, but also link it with them as well.  e.g. you should link
cannam@167: dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
cannam@167: dnl
cannam@167: dnl If you are only building threads programs, you may wish to
cannam@167: dnl use these variables in your default LIBS, CFLAGS, and CC:
cannam@167: dnl
cannam@167: dnl        LIBS="$PTHREAD_LIBS $LIBS"
cannam@167: dnl        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@167: dnl        CC="$PTHREAD_CC"
cannam@167: dnl
cannam@167: dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
cannam@167: dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE
cannam@167: dnl to that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
cannam@167: dnl
cannam@167: dnl ACTION-IF-FOUND is a list of shell commands to run if a threads
cannam@167: dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands
cannam@167: dnl to run it if it is not found.  If ACTION-IF-FOUND is not specified,
cannam@167: dnl the default action will define HAVE_PTHREAD.
cannam@167: dnl
cannam@167: dnl Please let the authors know if this macro fails on any platform,
cannam@167: dnl or if you have any other suggestions or comments.  This macro was
cannam@167: dnl based on work by SGJ on autoconf scripts for FFTW (www.fftw.org)
cannam@167: dnl (with help from M. Frigo), as well as ac_pthread and hb_pthread
cannam@167: dnl macros posted by Alejandro Forero Cuervo to the autoconf macro
cannam@167: dnl repository.  We are also grateful for the helpful feedback of
cannam@167: dnl numerous users.
cannam@167: dnl
cannam@167: dnl @version 2006-09-15
cannam@167: dnl @license GPLWithACException
cannam@167: dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
cannam@167: 
cannam@167: AC_DEFUN([ACX_PTHREAD], [
cannam@167: AC_REQUIRE([AC_CANONICAL_HOST])
cannam@167: AC_LANG_SAVE
cannam@167: AC_LANG_C
cannam@167: acx_pthread_ok=no
cannam@167: 
cannam@167: # We used to check for pthread.h first, but this fails if pthread.h
cannam@167: # requires special compiler flags (e.g. on True64 or Sequent).
cannam@167: # It gets checked for in the link test anyway.
cannam@167: 
cannam@167: # First of all, check if the user has set any of the PTHREAD_LIBS,
cannam@167: # etcetera environment variables, and if threads linking works using
cannam@167: # them:
cannam@167: if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
cannam@167:         save_CFLAGS="$CFLAGS"
cannam@167:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@167:         save_LIBS="$LIBS"
cannam@167:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@167:         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
cannam@167:         AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
cannam@167:         AC_MSG_RESULT($acx_pthread_ok)
cannam@167:         if test x"$acx_pthread_ok" = xno; then
cannam@167:                 PTHREAD_LIBS=""
cannam@167:                 PTHREAD_CFLAGS=""
cannam@167:         fi
cannam@167:         LIBS="$save_LIBS"
cannam@167:         CFLAGS="$save_CFLAGS"
cannam@167: fi
cannam@167: 
cannam@167: # We must check for the threads library under a number of different
cannam@167: # names; the ordering is very important because some systems
cannam@167: # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
cannam@167: # libraries is broken (non-POSIX).
cannam@167: 
cannam@167: # Create a list of thread flags to try.  Items starting with a "-" are
cannam@167: # C compiler flags, and other items are library names, except for "none"
cannam@167: # which indicates that we try without any flags at all, and "pthread-config"
cannam@167: # which is a program returning the flags for the Pth emulation library.
cannam@167: 
cannam@167: acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mt -mthreads pthread --thread-safe pthread-config"
cannam@167: 
cannam@167: # The ordering *is* (sometimes) important.  Some notes on the
cannam@167: # individual items follow:
cannam@167: 
cannam@167: # pthreads: AIX (must check this before -lpthread)
cannam@167: # none: in case threads are in libc; should be tried before -Kthread and
cannam@167: #       other compiler flags to prevent continual compiler warnings
cannam@167: # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
cannam@167: # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
cannam@167: # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
cannam@167: # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
cannam@167: # -pthreads: Solaris/gcc
cannam@167: # -mthreads: Mingw32/gcc, Lynx/gcc
cannam@167: # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
cannam@167: #      doesn't hurt to check since this sometimes defines pthreads too;
cannam@167: #      also defines -D_REENTRANT)
cannam@167: #      ... -mt is also the pthreads flag for HP/aCC
cannam@167: #           (where it should come before -mthreads to avoid spurious warnings)
cannam@167: # pthread: Linux, etcetera
cannam@167: # --thread-safe: KAI C++
cannam@167: # pthread-config: use pthread-config program (for GNU Pth library)
cannam@167: 
cannam@167: case "${host_cpu}-${host_os}" in
cannam@167:         *solaris*)
cannam@167: 
cannam@167:         # On Solaris (at least, for some versions), libc contains stubbed
cannam@167:         # (non-functional) versions of the pthreads routines, so link-based
cannam@167:         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
cannam@167:         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
cannam@167:         # a function called by this macro, so we could check for that, but
cannam@167:         # who knows whether they'll stub that too in a future libc.)  So,
cannam@167:         # we'll just look for -pthreads and -lpthread first:
cannam@167: 
cannam@167:         acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
cannam@167:         ;;
cannam@167: esac
cannam@167: 
cannam@167: if test x"$acx_pthread_ok" = xno; then
cannam@167: for flag in $acx_pthread_flags; do
cannam@167: 
cannam@167:         case $flag in
cannam@167:                 none)
cannam@167:                 AC_MSG_CHECKING([whether pthreads work without any flags])
cannam@167:                 ;;
cannam@167: 
cannam@167:                 -*)
cannam@167:                 AC_MSG_CHECKING([whether pthreads work with $flag])
cannam@167:                 PTHREAD_CFLAGS="$flag"
cannam@167:                 ;;
cannam@167: 
cannam@167: 		pthread-config)
cannam@167: 		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
cannam@167: 		if test x"$acx_pthread_config" = xno; then continue; fi
cannam@167: 		PTHREAD_CFLAGS="`pthread-config --cflags`"
cannam@167: 		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
cannam@167: 		;;
cannam@167: 
cannam@167:                 *)
cannam@167:                 AC_MSG_CHECKING([for the pthreads library -l$flag])
cannam@167:                 PTHREAD_LIBS="-l$flag"
cannam@167:                 ;;
cannam@167:         esac
cannam@167: 
cannam@167:         save_LIBS="$LIBS"
cannam@167:         save_CFLAGS="$CFLAGS"
cannam@167:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@167:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@167: 
cannam@167:         # Check for various functions.  We must include pthread.h,
cannam@167:         # since some functions may be macros.  (On the Sequent, we
cannam@167:         # need a special flag -Kthread to make this header compile.)
cannam@167:         # We check for pthread_join because it is in -lpthread on IRIX
cannam@167:         # while pthread_create is in libc.  We check for pthread_attr_init
cannam@167:         # due to DEC craziness with -lpthreads.  We check for
cannam@167:         # pthread_cleanup_push because it is one of the few pthread
cannam@167:         # functions on Solaris that doesn't have a non-functional libc stub.
cannam@167:         # We try pthread_create on general principles.
cannam@167:         AC_TRY_LINK([#include <pthread.h>],
cannam@167:                     [pthread_t th; pthread_join(th, (void**) 0);
cannam@167:                      pthread_attr_init((pthread_attr_t*) 0);
cannam@167:                      pthread_cleanup_push((void(*)(void *)) 0, (void*) 0);
cannam@167:                      pthread_create((pthread_t*) 0, (pthread_attr_t*) 0,
cannam@167:                                     (void*(*)(void *)) 0, (void*) 0);
cannam@167:                      pthread_cleanup_pop(0); ],
cannam@167:                     [acx_pthread_ok=yes])
cannam@167: 
cannam@167:         LIBS="$save_LIBS"
cannam@167:         CFLAGS="$save_CFLAGS"
cannam@167: 
cannam@167:         AC_MSG_RESULT($acx_pthread_ok)
cannam@167:         if test "x$acx_pthread_ok" = xyes; then
cannam@167:                 break;
cannam@167:         fi
cannam@167: 
cannam@167:         PTHREAD_LIBS=""
cannam@167:         PTHREAD_CFLAGS=""
cannam@167: done
cannam@167: fi
cannam@167: 
cannam@167: # Various other checks:
cannam@167: if test "x$acx_pthread_ok" = xyes; then
cannam@167:         save_LIBS="$LIBS"
cannam@167:         LIBS="$PTHREAD_LIBS $LIBS"
cannam@167:         save_CFLAGS="$CFLAGS"
cannam@167:         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
cannam@167: 
cannam@167:         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
cannam@167: 	AC_MSG_CHECKING([for joinable pthread attribute])
cannam@167: 	attr_name=unknown
cannam@167: 	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
cannam@167: 	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
cannam@167:                         [attr_name=$attr; break])
cannam@167: 	done
cannam@167:         AC_MSG_RESULT($attr_name)
cannam@167:         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
cannam@167:             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
cannam@167:                                [Define to necessary symbol if this constant
cannam@167:                                 uses a non-standard name on your system.])
cannam@167:         fi
cannam@167: 
cannam@167:         AC_MSG_CHECKING([if more special flags are required for pthreads])
cannam@167:         flag=no
cannam@167:         case "${host_cpu}-${host_os}" in
cannam@167:             *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
cannam@167:             *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
cannam@167:         esac
cannam@167:         AC_MSG_RESULT(${flag})
cannam@167:         if test "x$flag" != xno; then
cannam@167:             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
cannam@167:         fi
cannam@167: 
cannam@167:         LIBS="$save_LIBS"
cannam@167:         CFLAGS="$save_CFLAGS"
cannam@167: 
cannam@167:         # More AIX lossage: must compile with xlc_r or cc_r
cannam@167: 	if test x"$GCC" != xyes; then
cannam@167:           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
cannam@167:         else
cannam@167:           PTHREAD_CC=$CC
cannam@167: 	fi
cannam@167: else
cannam@167:         PTHREAD_CC="$CC"
cannam@167: fi
cannam@167: 
cannam@167: AC_SUBST(PTHREAD_LIBS)
cannam@167: AC_SUBST(PTHREAD_CFLAGS)
cannam@167: AC_SUBST(PTHREAD_CC)
cannam@167: 
cannam@167: # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
cannam@167: if test x"$acx_pthread_ok" = xyes; then
cannam@167:         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
cannam@167:         :
cannam@167: else
cannam@167:         acx_pthread_ok=no
cannam@167:         $2
cannam@167: fi
cannam@167: AC_LANG_RESTORE
cannam@167: ])dnl ACX_PTHREAD