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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@alum.mit.edu>
   57 #   Copyright (c) 2011 Daniel Richard G. <skunk@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 21
   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 $ax_pthread_flags"
  164         ;;
  165 	netbsd*)
  166 	# use libc stubs, don't link against libpthread, to allow
  167 	# dynamic loading
  168 	ax_pthread_flags=""
  169 	;;
  170 esac
  171 
  172 # Clang doesn't consider unrecognized options an error unless we specify
  173 # -Werror. We throw in some extra Clang-specific options to ensure that
  174 # this doesn't happen for GCC, which also accepts -Werror.
  175 
  176 AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
  177 save_CFLAGS="$CFLAGS"
  178 ax_pthread_extra_flags="-Werror"
  179 CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
  180 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
  181                   [AC_MSG_RESULT([yes])],
  182                   [ax_pthread_extra_flags=
  183                    AC_MSG_RESULT([no])])
  184 CFLAGS="$save_CFLAGS"
  185 
  186 if test x"$ax_pthread_ok" = xno; then
  187 for flag in $ax_pthread_flags; do
  188 
  189         case $flag in
  190                 none)
  191                 AC_MSG_CHECKING([whether pthreads work without any flags])
  192                 ;;
  193 
  194                 -*)
  195                 AC_MSG_CHECKING([whether pthreads work with $flag])
  196                 PTHREAD_CFLAGS="$flag"
  197                 ;;
  198 
  199                 pthread-config)
  200                 AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
  201                 if test x"$ax_pthread_config" = xno; then continue; fi
  202                 PTHREAD_CFLAGS="`pthread-config --cflags`"
  203                 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
  204                 ;;
  205 
  206                 *)
  207                 AC_MSG_CHECKING([for the pthreads library -l$flag])
  208                 PTHREAD_LIBS="-l$flag"
  209                 ;;
  210         esac
  211 
  212         save_LIBS="$LIBS"
  213         save_CFLAGS="$CFLAGS"
  214         LIBS="$PTHREAD_LIBS $LIBS"
  215         CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ax_pthread_extra_flags"
  216 
  217         # Check for various functions.  We must include pthread.h,
  218         # since some functions may be macros.  (On the Sequent, we
  219         # need a special flag -Kthread to make this header compile.)
  220         # We check for pthread_join because it is in -lpthread on IRIX
  221         # while pthread_create is in libc.  We check for pthread_attr_init
  222         # due to DEC craziness with -lpthreads.  We check for
  223         # pthread_cleanup_push because it is one of the few pthread
  224         # functions on Solaris that doesn't have a non-functional libc stub.
  225         # We try pthread_create on general principles.
  226         AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
  227                         static void routine(void *a) { a = 0; }
  228                         static void *start_routine(void *a) { return a; }],
  229                        [pthread_t th; pthread_attr_t attr;
  230                         pthread_create(&th, 0, start_routine, 0);
  231                         pthread_join(th, 0);
  232                         pthread_attr_init(&attr);
  233                         pthread_cleanup_push(routine, 0);
  234                         pthread_cleanup_pop(0) /* ; */])],
  235                 [ax_pthread_ok=yes],
  236                 [])
  237 
  238         LIBS="$save_LIBS"
  239         CFLAGS="$save_CFLAGS"
  240 
  241         AC_MSG_RESULT([$ax_pthread_ok])
  242         if test "x$ax_pthread_ok" = xyes; then
  243                 break;
  244         fi
  245 
  246         PTHREAD_LIBS=""
  247         PTHREAD_CFLAGS=""
  248 done
  249 fi
  250 
  251 # Various other checks:
  252 if test "x$ax_pthread_ok" = xyes; then
  253         save_LIBS="$LIBS"
  254         LIBS="$PTHREAD_LIBS $LIBS"
  255         save_CFLAGS="$CFLAGS"
  256         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
  257 
  258         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
  259         AC_MSG_CHECKING([for joinable pthread attribute])
  260         attr_name=unknown
  261         for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
  262             AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
  263                            [int attr = $attr; return attr /* ; */])],
  264                 [attr_name=$attr; break],
  265                 [])
  266         done
  267         AC_MSG_RESULT([$attr_name])
  268         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
  269             AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
  270                                [Define to necessary symbol if this constant
  271                                 uses a non-standard name on your system.])
  272         fi
  273 
  274         AC_MSG_CHECKING([if more special flags are required for pthreads])
  275         flag=no
  276         case ${host_os} in
  277             aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
  278             osf* | hpux*) flag="-D_REENTRANT";;
  279             solaris*)
  280             if test "$GCC" = "yes"; then
  281                 flag="-D_REENTRANT"
  282             else
  283                 # TODO: What about Clang on Solaris?
  284                 flag="-mt -D_REENTRANT"
  285             fi
  286             ;;
  287         esac
  288         AC_MSG_RESULT([$flag])
  289         if test "x$flag" != xno; then
  290             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
  291         fi
  292 
  293         AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
  294             [ax_cv_PTHREAD_PRIO_INHERIT], [
  295                 AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
  296                                                 [[int i = PTHREAD_PRIO_INHERIT;]])],
  297                     [ax_cv_PTHREAD_PRIO_INHERIT=yes],
  298                     [ax_cv_PTHREAD_PRIO_INHERIT=no])
  299             ])
  300         AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
  301             [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
  302 
  303         LIBS="$save_LIBS"
  304         CFLAGS="$save_CFLAGS"
  305 
  306         # More AIX lossage: compile with *_r variant
  307         if test "x$GCC" != xyes; then
  308             case $host_os in
  309                 aix*)
  310                 AS_CASE(["x/$CC"],
  311                   [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
  312                   [#handle absolute path differently from PATH based program lookup
  313                    AS_CASE(["x$CC"],
  314                      [x/*],
  315                      [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
  316                      [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
  317                 ;;
  318             esac
  319         fi
  320 fi
  321 
  322 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
  323 
  324 AC_SUBST([PTHREAD_LIBS])
  325 AC_SUBST([PTHREAD_CFLAGS])
  326 AC_SUBST([PTHREAD_CC])
  327 
  328 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
  329 if test x"$ax_pthread_ok" = xyes; then
  330         ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
  331         :
  332 else
  333         ax_pthread_ok=no
  334         $2
  335 fi
  336 AC_LANG_POP
  337 ])dnl AX_PTHREAD