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   1 ##### http://autoconf-archive.cryp.to/acx_pthread.html
   2 #
   3 # SYNOPSIS
   4 #
   5 #   ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
   6 #
   7 # DESCRIPTION
   8 #
   9 #   This macro figures out how to build C programs using POSIX threads.
  10 #   It sets the PTHREAD_LIBS output variable to the threads library and
  11 #   linker flags, and the PTHREAD_CFLAGS output variable to any special
  12 #   C compiler flags that are needed. (The user can also force certain
  13 #   compiler flags/libs to be tested by setting these environment
  14 #   variables.)
  15 #
  16 #   Also sets PTHREAD_CC to any special C compiler that is needed for
  17 #   multi-threaded programs (defaults to the value of CC otherwise).
  18 #   (This is necessary on AIX to use the special cc_r compiler alias.)
  19 #
  20 #   NOTE: You are assumed to not only compile your program with these
  21 #   flags, but also link it with them as well. e.g. you should link
  22 #   with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS
  23 #   $LIBS
  24 #
  25 #   If you are only building threads programs, you may wish to use
  26 #   these variables in your default LIBS, CFLAGS, and CC:
  27 #
  28 #          LIBS="$PTHREAD_LIBS $LIBS"
  29 #          CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
  30 #          CC="$PTHREAD_CC"
  31 #
  32 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
  33 #   constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
  34 #   that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
  35 #
  36 #   ACTION-IF-FOUND is a list of shell commands to run if a threads
  37 #   library is found, and ACTION-IF-NOT-FOUND is a list of commands to
  38 #   run it if it is not found. If ACTION-IF-FOUND is not specified, the
  39 #   default action will define HAVE_PTHREAD.
  40 #
  41 #   Please let the authors know if this macro fails on any platform, or
  42 #   if you have any other suggestions or comments. This macro was based
  43 #   on work by SGJ on autoconf scripts for FFTW (http://www.fftw.org/)
  44 #   (with help from M. Frigo), as well as ac_pthread and hb_pthread
  45 #   macros posted by Alejandro Forero Cuervo to the autoconf macro
  46 #   repository. We are also grateful for the helpful feedback of
  47 #   numerous users.
  48 #
  49 # LAST MODIFICATION
  50 #
  51 #   2006-05-29
  52 #
  53 # COPYLEFT
  54 #
  55 #   Copyright (c) 2006 Steven G. Johnson <stevenj@alum.mit.edu>
  56 #
  57 #   This program is free software; you can redistribute it and/or
  58 #   modify it under the terms of the GNU General Public License as
  59 #   published by the Free Software Foundation; either version 2 of the
  60 #   License, or (at your option) any later version.
  61 #
  62 #   This program is distributed in the hope that it will be useful, but
  63 #   WITHOUT ANY WARRANTY; without even the implied warranty of
  64 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  65 #   General Public License for more details.
  66 #
  67 #   You should have received a copy of the GNU General Public License
  68 #   along with this program; if not, write to the Free Software
  69 #   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  70 #   02111-1307, USA.
  71 #
  72 #   As a special exception, the respective Autoconf Macro's copyright
  73 #   owner gives unlimited permission to copy, distribute and modify the
  74 #   configure scripts that are the output of Autoconf when processing
  75 #   the Macro. You need not follow the terms of the GNU General Public
  76 #   License when using or distributing such scripts, even though
  77 #   portions of the text of the Macro appear in them. The GNU General
  78 #   Public License (GPL) does govern all other use of the material that
  79 #   constitutes the Autoconf Macro.
  80 #
  81 #   This special exception to the GPL applies to versions of the
  82 #   Autoconf Macro released by the Autoconf Macro Archive. When you
  83 #   make and distribute a modified version of the Autoconf Macro, you
  84 #   may extend this special exception to the GPL to apply to your
  85 #   modified version as well.
  86
  87 AC_DEFUN([ACX_PTHREAD], [
  88 AC_REQUIRE([AC_CANONICAL_HOST])
  89 AC_LANG_PUSH([C])
  90 acx_pthread_ok=no
  91
  92 # We used to check for pthread.h first, but this fails if pthread.h
  93 # requires special compiler flags (e.g. on True64 or Sequent).
  94 # It gets checked for in the link test anyway.
  95
  96 # First of all, check if the user has set any of the PTHREAD_LIBS,
  97 # etcetera environment variables, and if threads linking works using
  98 # them:
  99 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
 100         save_CFLAGS="$CFLAGS"
 101         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
 102         save_LIBS="$LIBS"
 103         LIBS="$PTHREAD_LIBS $LIBS"
 104         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
 105         AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
 106         AC_MSG_RESULT($acx_pthread_ok)
 107         if test x"$acx_pthread_ok" = xno; then
 108                 PTHREAD_LIBS=""
 109                 PTHREAD_CFLAGS=""
 110         fi
 111         LIBS="$save_LIBS"
 112         CFLAGS="$save_CFLAGS"
 113 fi
 114
 115 # We must check for the threads library under a number of different
 116 # names; the ordering is very important because some systems
 117 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
 118 # libraries is broken (non-POSIX).
 119
 120 # Create a list of thread flags to try.  Items starting with a "-" are
 121 # C compiler flags, and other items are library names, except for "none"
 122 # which indicates that we try without any flags at all, and "pthread-config"
 123 # which is a program returning the flags for the Pth emulation library.
 124
 125 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
 126
 127 # The ordering *is* (sometimes) important.  Some notes on the
 128 # individual items follow:
 129
 130 # pthreads: AIX (must check this before -lpthread)
 131 # none: in case threads are in libc; should be tried before -Kthread and
 132 #       other compiler flags to prevent continual compiler warnings
 133 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
 134 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
 135 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
 136 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
 137 # -pthreads: Solaris/gcc
 138 # -mthreads: Mingw32/gcc, Lynx/gcc
 139 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
 140 #      doesn't hurt to check since this sometimes defines pthreads too;
 141 #      also defines -D_REENTRANT)
 142 #      ... -mt is also the pthreads flag for HP/aCC
 143 # pthread: Linux, etcetera
 144 # --thread-safe: KAI C++
 145 # pthread-config: use pthread-config program (for GNU Pth library)
 146
 147 case "${host_cpu}-${host_os}" in
 148         *solaris*)
 149
 150         # On Solaris (at least, for some versions), libc contains stubbed
 151         # (non-functional) versions of the pthreads routines, so link-based
 152         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
 153         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
 154         # a function called by this macro, so we could check for that, but
 155         # who knows whether they'll stub that too in a future libc.)  So,
 156         # we'll just look for -pthreads and -lpthread first:
 157
 158         acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
 159         ;;
 160 esac
 161
 162 if test x"$acx_pthread_ok" = xno; then
 163 for flag in $acx_pthread_flags; do
 164
 165         case $flag in
 166                 none)
 167                 AC_MSG_CHECKING([whether pthreads work without any flags])
 168                 ;;
 169
 170                 -*)
 171                 AC_MSG_CHECKING([whether pthreads work with $flag])
 172                 PTHREAD_CFLAGS="$flag"
 173                 ;;
 174
 175                 pthread-config)
 176                 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
 177                 if test x"$acx_pthread_config" = xno; then continue; fi
 178                 PTHREAD_CFLAGS="`pthread-config --cflags`"
 179                 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
 180                 ;;
 181
 182                 *)
 183                 AC_MSG_CHECKING([for the pthreads library -l$flag])
 184                 PTHREAD_LIBS="-l$flag"
 185                 ;;
 186         esac
 187
 188         save_LIBS="$LIBS"
 189         save_CFLAGS="$CFLAGS"
 190         LIBS="$PTHREAD_LIBS $LIBS"
 191         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
 192
 193         # Check for various functions.  We must include pthread.h,
 194         # since some functions may be macros.  (On the Sequent, we
 195         # need a special flag -Kthread to make this header compile.)
 196         # We check for pthread_join because it is in -lpthread on IRIX
 197         # while pthread_create is in libc.  We check for pthread_attr_init
 198         # due to DEC craziness with -lpthreads.  We check for
 199         # pthread_cleanup_push because it is one of the few pthread
 200         # functions on Solaris that doesn't have a non-functional libc stub.
 201         # We try pthread_create on general principles.
 202         AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], [[pthread_t th; pthread_join(th, 0);
 203                      pthread_attr_init(0); pthread_cleanup_push(0, 0);
 204                      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ]])],[acx_pthread_ok=yes],[])
 205
 206         LIBS="$save_LIBS"
 207         CFLAGS="$save_CFLAGS"
 208
 209         AC_MSG_RESULT($acx_pthread_ok)
 210         if test "x$acx_pthread_ok" = xyes; then
 211                 break;
 212         fi
 213
 214         PTHREAD_LIBS=""
 215         PTHREAD_CFLAGS=""
 216 done
 217 fi
 218
 219 # Various other checks:
 220 if test "x$acx_pthread_ok" = xyes; then
 221         save_LIBS="$LIBS"
 222         LIBS="$PTHREAD_LIBS $LIBS"
 223         save_CFLAGS="$CFLAGS"
 224         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
 225
 226         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
 227         AC_MSG_CHECKING([for joinable pthread attribute])
 228         attr_name=unknown
 229         for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
 230             AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], [[int attr=$attr; return attr;]])],[attr_name=$attr; break],[])
 231         done
 232         AC_MSG_RESULT($attr_name)
 233         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
 234             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
 235                                [Define to necessary symbol if this constant
 236                                 uses a non-standard name on your system.])
 237         fi
 238
 239         AC_MSG_CHECKING([if more special flags are required for pthreads])
 240         flag=no
 241         case "${host_cpu}-${host_os}" in
 242             *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
 243             *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
 244         esac
 245         AC_MSG_RESULT(${flag})
 246         if test "x$flag" != xno; then
 247             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
 248         fi
 249
 250         LIBS="$save_LIBS"
 251         CFLAGS="$save_CFLAGS"
 252
 253         # More AIX lossage: must compile with xlc_r or cc_r
 254         if test x"$GCC" != xyes; then
 255           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
 256         else
 257           PTHREAD_CC=$CC
 258         fi
 259 else
 260         PTHREAD_CC="$CC"
 261 fi
 262
 263 AC_SUBST(PTHREAD_LIBS)
 264 AC_SUBST(PTHREAD_CFLAGS)
 265 AC_SUBST(PTHREAD_CC)
 266
 267 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
 268 if test x"$acx_pthread_ok" = xyes; then
 269         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
 270         :
 271 else
 272         acx_pthread_ok=no
 273         $2
 274 fi
 275 AC_LANG_POP([])
 276 ])dnl ACX_PTHREAD