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      1 # ===========================================================================
      2 #        http://www.gnu.org/software/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 #   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
     37 #   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
     38 #   PTHREAD_CFLAGS.
     39 #
     40 #   ACTION-IF-FOUND is a list of shell commands to run if a threads library
     41 #   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
     42 #   is not found. If ACTION-IF-FOUND is not specified, the default action
     43 #   will define HAVE_PTHREAD.
     44 #
     45 #   Please let the authors know if this macro fails on any platform, or if
     46 #   you have any other suggestions or comments. This macro was based on work
     47 #   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
     48 #   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
     49 #   Alejandro Forero Cuervo to the autoconf macro repository. We are also
     50 #   grateful for the helpful feedback of numerous users.
     51 #
     52 #   Updated for Autoconf 2.68 by Daniel Richard G.
     53 #
     54 # LICENSE
     55 #
     56 #   Copyright (c) 2008 Steven G. Johnson <stevenj (a] alum.mit.edu>
     57 #   Copyright (c) 2011 Daniel Richard G. <skunk (a] iSKUNK.ORG>
     58 #
     59 #   This program is free software: you can redistribute it and/or modify it
     60 #   under the terms of the GNU General Public License as published by the
     61 #   Free Software Foundation, either version 3 of the License, or (at your
     62 #   option) any later version.
     63 #
     64 #   This program is distributed in the hope that it will be useful, but
     65 #   WITHOUT ANY WARRANTY; without even the implied warranty of
     66 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
     67 #   Public License for more details.
     68 #
     69 #   You should have received a copy of the GNU General Public License along
     70 #   with this program. If not, see <http://www.gnu.org/licenses/>.
     71 #
     72 #   As a special exception, the respective Autoconf Macro's copyright owner
     73 #   gives unlimited permission to copy, distribute and modify the configure
     74 #   scripts that are the output of Autoconf when processing the Macro. You
     75 #   need not follow the terms of the GNU General Public License when using
     76 #   or distributing such scripts, even though portions of the text of the
     77 #   Macro appear in them. The GNU General Public License (GPL) does govern
     78 #   all other use of the material that constitutes the Autoconf Macro.
     79 #
     80 #   This special exception to the GPL applies to versions of the Autoconf
     81 #   Macro released by the Autoconf Archive. When you make and distribute a
     82 #   modified version of the Autoconf Macro, you may extend this special
     83 #   exception to the GPL to apply to your modified version as well.
     84 
     85 #serial 18
     86 
     87 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
     88 AC_DEFUN([AX_PTHREAD], [
     89 AC_REQUIRE([AC_CANONICAL_HOST])
     90 AC_LANG_PUSH([C])
     91 ax_pthread_ok=no
     92 
     93 # We used to check for pthread.h first, but this fails if pthread.h
     94 # requires special compiler flags (e.g. on True64 or Sequent).
     95 # It gets checked for in the link test anyway.
     96 
     97 # First of all, check if the user has set any of the PTHREAD_LIBS,
     98 # etcetera environment variables, and if threads linking works using
     99 # them:
    100 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
    101         save_CFLAGS="$CFLAGS"
    102         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    103         save_LIBS="$LIBS"
    104         LIBS="$PTHREAD_LIBS $LIBS"
    105         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
    106         AC_TRY_LINK_FUNC(pthread_join, ax_pthread_ok=yes)
    107         AC_MSG_RESULT($ax_pthread_ok)
    108         if test x"$ax_pthread_ok" = xno; then
    109                 PTHREAD_LIBS=""
    110                 PTHREAD_CFLAGS=""
    111         fi
    112         LIBS="$save_LIBS"
    113         CFLAGS="$save_CFLAGS"
    114 fi
    115 
    116 # We must check for the threads library under a number of different
    117 # names; the ordering is very important because some systems
    118 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
    119 # libraries is broken (non-POSIX).
    120 
    121 # Create a list of thread flags to try.  Items starting with a "-" are
    122 # C compiler flags, and other items are library names, except for "none"
    123 # which indicates that we try without any flags at all, and "pthread-config"
    124 # which is a program returning the flags for the Pth emulation library.
    125 
    126 ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
    127 
    128 # The ordering *is* (sometimes) important.  Some notes on the
    129 # individual items follow:
    130 
    131 # pthreads: AIX (must check this before -lpthread)
    132 # none: in case threads are in libc; should be tried before -Kthread and
    133 #       other compiler flags to prevent continual compiler warnings
    134 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
    135 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
    136 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
    137 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
    138 # -pthreads: Solaris/gcc
    139 # -mthreads: Mingw32/gcc, Lynx/gcc
    140 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
    141 #      doesn't hurt to check since this sometimes defines pthreads too;
    142 #      also defines -D_REENTRANT)
    143 #      ... -mt is also the pthreads flag for HP/aCC
    144 # pthread: Linux, etcetera
    145 # --thread-safe: KAI C++
    146 # pthread-config: use pthread-config program (for GNU Pth library)
    147 
    148 case ${host_os} in
    149         solaris*)
    150 
    151         # On Solaris (at least, for some versions), libc contains stubbed
    152         # (non-functional) versions of the pthreads routines, so link-based
    153         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
    154         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
    155         # a function called by this macro, so we could check for that, but
    156         # who knows whether they'll stub that too in a future libc.)  So,
    157         # we'll just look for -pthreads and -lpthread first:
    158 
    159         ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
    160         ;;
    161 
    162         darwin*)
    163         ax_pthread_flags="-pthread $ax_pthread_flags"
    164         ;;
    165 esac
    166 
    167 if test x"$ax_pthread_ok" = xno; then
    168 for flag in $ax_pthread_flags; do
    169 
    170         case $flag in
    171                 none)
    172                 AC_MSG_CHECKING([whether pthreads work without any flags])
    173                 ;;
    174 
    175                 -*)
    176                 AC_MSG_CHECKING([whether pthreads work with $flag])
    177                 PTHREAD_CFLAGS="$flag"
    178                 ;;
    179 
    180                 pthread-config)
    181                 AC_CHECK_PROG(ax_pthread_config, pthread-config, yes, no)
    182                 if test x"$ax_pthread_config" = xno; then continue; fi
    183                 PTHREAD_CFLAGS="`pthread-config --cflags`"
    184                 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
    185                 ;;
    186 
    187                 *)
    188                 AC_MSG_CHECKING([for the pthreads library -l$flag])
    189                 PTHREAD_LIBS="-l$flag"
    190                 ;;
    191         esac
    192 
    193         save_LIBS="$LIBS"
    194         save_CFLAGS="$CFLAGS"
    195         LIBS="$PTHREAD_LIBS $LIBS"
    196         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    197 
    198         # Check for various functions.  We must include pthread.h,
    199         # since some functions may be macros.  (On the Sequent, we
    200         # need a special flag -Kthread to make this header compile.)
    201         # We check for pthread_join because it is in -lpthread on IRIX
    202         # while pthread_create is in libc.  We check for pthread_attr_init
    203         # due to DEC craziness with -lpthreads.  We check for
    204         # pthread_cleanup_push because it is one of the few pthread
    205         # functions on Solaris that doesn't have a non-functional libc stub.
    206         # We try pthread_create on general principles.
    207         AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
    208                         static void routine(void *a) { a = 0; }
    209                         static void *start_routine(void *a) { return a; }],
    210                        [pthread_t th; pthread_attr_t attr;
    211                         pthread_create(&th, 0, start_routine, 0);
    212                         pthread_join(th, 0);
    213                         pthread_attr_init(&attr);
    214                         pthread_cleanup_push(routine, 0);
    215                         pthread_cleanup_pop(0) /* ; */])],
    216                 [ax_pthread_ok=yes],
    217                 [])
    218 
    219         LIBS="$save_LIBS"
    220         CFLAGS="$save_CFLAGS"
    221 
    222         AC_MSG_RESULT($ax_pthread_ok)
    223         if test "x$ax_pthread_ok" = xyes; then
    224                 break;
    225         fi
    226 
    227         PTHREAD_LIBS=""
    228         PTHREAD_CFLAGS=""
    229 done
    230 fi
    231 
    232 # Various other checks:
    233 if test "x$ax_pthread_ok" = xyes; then
    234         save_LIBS="$LIBS"
    235         LIBS="$PTHREAD_LIBS $LIBS"
    236         save_CFLAGS="$CFLAGS"
    237         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    238 
    239         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
    240         AC_MSG_CHECKING([for joinable pthread attribute])
    241         attr_name=unknown
    242         for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
    243             AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
    244                            [int attr = $attr; return attr /* ; */])],
    245                 [attr_name=$attr; break],
    246                 [])
    247         done
    248         AC_MSG_RESULT($attr_name)
    249         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
    250             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
    251                                [Define to necessary symbol if this constant
    252                                 uses a non-standard name on your system.])
    253         fi
    254 
    255         AC_MSG_CHECKING([if more special flags are required for pthreads])
    256         flag=no
    257         case ${host_os} in
    258             aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
    259             osf* | hpux*) flag="-D_REENTRANT";;
    260             solaris*)
    261             if test "$GCC" = "yes"; then
    262                 flag="-D_REENTRANT"
    263             else
    264                 flag="-mt -D_REENTRANT"
    265             fi
    266             ;;
    267         esac
    268         AC_MSG_RESULT(${flag})
    269         if test "x$flag" != xno; then
    270             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
    271         fi
    272 
    273         AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
    274             ax_cv_PTHREAD_PRIO_INHERIT, [
    275                 AC_LINK_IFELSE([
    276                     AC_LANG_PROGRAM([[#include <pthread.h>]], [[int i = PTHREAD_PRIO_INHERIT;]])],
    277                     [ax_cv_PTHREAD_PRIO_INHERIT=yes],
    278                     [ax_cv_PTHREAD_PRIO_INHERIT=no])
    279             ])
    280         AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
    281             AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], 1, [Have PTHREAD_PRIO_INHERIT.]))
    282 
    283         LIBS="$save_LIBS"
    284         CFLAGS="$save_CFLAGS"
    285 
    286         # More AIX lossage: must compile with xlc_r or cc_r
    287         if test x"$GCC" != xyes; then
    288           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
    289         else
    290           PTHREAD_CC=$CC
    291         fi
    292 else
    293         PTHREAD_CC="$CC"
    294 fi
    295 
    296 AC_SUBST(PTHREAD_LIBS)
    297 AC_SUBST(PTHREAD_CFLAGS)
    298 AC_SUBST(PTHREAD_CC)
    299 
    300 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
    301 if test x"$ax_pthread_ok" = xyes; then
    302         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
    303         :
    304 else
    305         ax_pthread_ok=no
    306         $2
    307 fi
    308 AC_LANG_POP
    309 ])dnl AX_PTHREAD
    310