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      1 # ===========================================================================
      2 #           http://www.nongnu.org/autoconf-archive/ax_pthread.html
      3 # ===========================================================================
      4 #
      5 # SYNOPSIS
      6 #
      7 #   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
      8 #
      9 # DESCRIPTION
     10 #
     11 #   This macro figures out how to build C programs using POSIX threads. It
     12 #   sets the PTHREAD_LIBS output variable to the threads library and linker
     13 #   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
     14 #   flags that are needed. (The user can also force certain compiler
     15 #   flags/libs to be tested by setting these environment variables.)
     16 #
     17 #   Also sets PTHREAD_CC to any special C compiler that is needed for
     18 #   multi-threaded programs (defaults to the value of CC otherwise). (This
     19 #   is necessary on AIX to use the special cc_r compiler alias.)
     20 #
     21 #   NOTE: You are assumed to not only compile your program with these flags,
     22 #   but also link it with them as well. e.g. you should link with
     23 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
     24 #
     25 #   If you are only building threads programs, you may wish to use these
     26 #   variables in your default LIBS, CFLAGS, and CC:
     27 #
     28 #     LIBS="$PTHREAD_LIBS $LIBS"
     29 #     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
     30 #     CC="$PTHREAD_CC"
     31 #
     32 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
     33 #   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
     34 #   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
     35 #
     36 #   ACTION-IF-FOUND is a list of shell commands to run if a threads library
     37 #   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
     38 #   is not found. If ACTION-IF-FOUND is not specified, the default action
     39 #   will define HAVE_PTHREAD.
     40 #
     41 #   Please let the authors know if this macro fails on any platform, or if
     42 #   you have any other suggestions or comments. This macro was based on work
     43 #   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
     44 #   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
     45 #   Alejandro Forero Cuervo to the autoconf macro repository. We are also
     46 #   grateful for the helpful feedback of numerous users.
     47 #
     48 # LICENSE
     49 #
     50 #   Copyright (c) 2008 Steven G. Johnson <stevenj (a] alum.mit.edu>
     51 #
     52 #   This program is free software: you can redistribute it and/or modify it
     53 #   under the terms of the GNU General Public License as published by the
     54 #   Free Software Foundation, either version 3 of the License, or (at your
     55 #   option) any later version.
     56 #
     57 #   This program is distributed in the hope that it will be useful, but
     58 #   WITHOUT ANY WARRANTY; without even the implied warranty of
     59 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
     60 #   Public License for more details.
     61 #
     62 #   You should have received a copy of the GNU General Public License along
     63 #   with this program. If not, see <http://www.gnu.org/licenses/>.
     64 #
     65 #   As a special exception, the respective Autoconf Macro's copyright owner
     66 #   gives unlimited permission to copy, distribute and modify the configure
     67 #   scripts that are the output of Autoconf when processing the Macro. You
     68 #   need not follow the terms of the GNU General Public License when using
     69 #   or distributing such scripts, even though portions of the text of the
     70 #   Macro appear in them. The GNU General Public License (GPL) does govern
     71 #   all other use of the material that constitutes the Autoconf Macro.
     72 #
     73 #   This special exception to the GPL applies to versions of the Autoconf
     74 #   Macro released by the Autoconf Archive. When you make and distribute a
     75 #   modified version of the Autoconf Macro, you may extend this special
     76 #   exception to the GPL to apply to your modified version as well.
     77 
     78 #serial 6
     79 
     80 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
     81 AC_DEFUN([AX_PTHREAD], [
     82 AC_REQUIRE([AC_CANONICAL_HOST])
     83 AC_LANG_SAVE
     84 AC_LANG_C
     85 ax_pthread_ok=no
     86 
     87 # We used to check for pthread.h first, but this fails if pthread.h
     88 # requires special compiler flags (e.g. on True64 or Sequent).
     89 # It gets checked for in the link test anyway.
     90 
     91 # First of all, check if the user has set any of the PTHREAD_LIBS,
     92 # etcetera environment variables, and if threads linking works using
     93 # them:
     94 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
     95         save_CFLAGS="$CFLAGS"
     96         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
     97         save_LIBS="$LIBS"
     98         LIBS="$PTHREAD_LIBS $LIBS"
     99         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
    100         AC_TRY_LINK_FUNC(pthread_join, ax_pthread_ok=yes)
    101         AC_MSG_RESULT($ax_pthread_ok)
    102         if test x"$ax_pthread_ok" = xno; then
    103                 PTHREAD_LIBS=""
    104                 PTHREAD_CFLAGS=""
    105         fi
    106         LIBS="$save_LIBS"
    107         CFLAGS="$save_CFLAGS"
    108 fi
    109 
    110 # We must check for the threads library under a number of different
    111 # names; the ordering is very important because some systems
    112 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
    113 # libraries is broken (non-POSIX).
    114 
    115 # Create a list of thread flags to try.  Items starting with a "-" are
    116 # C compiler flags, and other items are library names, except for "none"
    117 # which indicates that we try without any flags at all, and "pthread-config"
    118 # which is a program returning the flags for the Pth emulation library.
    119 
    120 ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
    121 
    122 # The ordering *is* (sometimes) important.  Some notes on the
    123 # individual items follow:
    124 
    125 # pthreads: AIX (must check this before -lpthread)
    126 # none: in case threads are in libc; should be tried before -Kthread and
    127 #       other compiler flags to prevent continual compiler warnings
    128 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
    129 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
    130 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
    131 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
    132 # -pthreads: Solaris/gcc
    133 # -mthreads: Mingw32/gcc, Lynx/gcc
    134 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
    135 #      doesn't hurt to check since this sometimes defines pthreads too;
    136 #      also defines -D_REENTRANT)
    137 #      ... -mt is also the pthreads flag for HP/aCC
    138 # pthread: Linux, etcetera
    139 # --thread-safe: KAI C++
    140 # pthread-config: use pthread-config program (for GNU Pth library)
    141 
    142 case "${host_cpu}-${host_os}" in
    143         *solaris*)
    144 
    145         # On Solaris (at least, for some versions), libc contains stubbed
    146         # (non-functional) versions of the pthreads routines, so link-based
    147         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
    148         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
    149         # a function called by this macro, so we could check for that, but
    150         # who knows whether they'll stub that too in a future libc.)  So,
    151         # we'll just look for -pthreads and -lpthread first:
    152 
    153         ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
    154         ;;
    155 
    156 	*-darwin*)
    157 	acx_pthread_flags="-pthread $acx_pthread_flags"
    158 	;;
    159 esac
    160 
    161 if test x"$ax_pthread_ok" = xno; then
    162 for flag in $ax_pthread_flags; do
    163 
    164         case $flag in
    165                 none)
    166                 AC_MSG_CHECKING([whether pthreads work without any flags])
    167                 ;;
    168 
    169                 -*)
    170                 AC_MSG_CHECKING([whether pthreads work with $flag])
    171                 PTHREAD_CFLAGS="$flag"
    172                 ;;
    173 
    174 		pthread-config)
    175 		AC_CHECK_PROG(ax_pthread_config, pthread-config, yes, no)
    176 		if test x"$ax_pthread_config" = xno; then continue; fi
    177 		PTHREAD_CFLAGS="`pthread-config --cflags`"
    178 		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
    179 		;;
    180 
    181                 *)
    182                 AC_MSG_CHECKING([for the pthreads library -l$flag])
    183                 PTHREAD_LIBS="-l$flag"
    184                 ;;
    185         esac
    186 
    187         save_LIBS="$LIBS"
    188         save_CFLAGS="$CFLAGS"
    189         LIBS="$PTHREAD_LIBS $LIBS"
    190         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    191 
    192         # Check for various functions.  We must include pthread.h,
    193         # since some functions may be macros.  (On the Sequent, we
    194         # need a special flag -Kthread to make this header compile.)
    195         # We check for pthread_join because it is in -lpthread on IRIX
    196         # while pthread_create is in libc.  We check for pthread_attr_init
    197         # due to DEC craziness with -lpthreads.  We check for
    198         # pthread_cleanup_push because it is one of the few pthread
    199         # functions on Solaris that doesn't have a non-functional libc stub.
    200         # We try pthread_create on general principles.
    201         AC_TRY_LINK([#include <pthread.h>
    202 	             static void routine(void* a) {a=0;}
    203 	             static void* start_routine(void* a) {return a;}],
    204                     [pthread_t th; pthread_attr_t attr;
    205                      pthread_join(th, 0);
    206                      pthread_attr_init(&attr);
    207                      pthread_cleanup_push(routine, 0);
    208                      pthread_create(&th,0,start_routine,0);
    209                      pthread_cleanup_pop(0); ],
    210                     [ax_pthread_ok=yes])
    211 
    212         LIBS="$save_LIBS"
    213         CFLAGS="$save_CFLAGS"
    214 
    215         AC_MSG_RESULT($ax_pthread_ok)
    216         if test "x$ax_pthread_ok" = xyes; then
    217                 break;
    218         fi
    219 
    220         PTHREAD_LIBS=""
    221         PTHREAD_CFLAGS=""
    222 done
    223 fi
    224 
    225 # Various other checks:
    226 if test "x$ax_pthread_ok" = xyes; then
    227         save_LIBS="$LIBS"
    228         LIBS="$PTHREAD_LIBS $LIBS"
    229         save_CFLAGS="$CFLAGS"
    230         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    231 
    232         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
    233 	AC_MSG_CHECKING([for joinable pthread attribute])
    234 	attr_name=unknown
    235 	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
    236 	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
    237                         [attr_name=$attr; break])
    238 	done
    239         AC_MSG_RESULT($attr_name)
    240         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
    241             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
    242                                [Define to necessary symbol if this constant
    243                                 uses a non-standard name on your system.])
    244         fi
    245 
    246         AC_MSG_CHECKING([if more special flags are required for pthreads])
    247         flag=no
    248         case "${host_cpu}-${host_os}" in
    249             *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
    250             *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
    251         esac
    252         AC_MSG_RESULT(${flag})
    253         if test "x$flag" != xno; then
    254             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
    255         fi
    256 
    257         LIBS="$save_LIBS"
    258         CFLAGS="$save_CFLAGS"
    259 
    260         # More AIX lossage: must compile with xlc_r or cc_r
    261 	if test x"$GCC" != xyes; then
    262           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
    263         else
    264           PTHREAD_CC=$CC
    265 	fi
    266 else
    267         PTHREAD_CC="$CC"
    268 fi
    269 
    270 AC_SUBST(PTHREAD_LIBS)
    271 AC_SUBST(PTHREAD_CFLAGS)
    272 AC_SUBST(PTHREAD_CC)
    273 
    274 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
    275 if test x"$ax_pthread_ok" = xyes; then
    276         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
    277         :
    278 else
    279         ax_pthread_ok=no
    280         $2
    281 fi
    282 AC_LANG_RESTORE
    283 ])dnl AX_PTHREAD