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     1 # This was retrieved from

     2 #    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?revision=1277&root=avahi

     3 # See also (perhaps for new versions?)

     4 #    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?root=avahi

5 #

     6 # We've rewritten the inconsistency check code (from avahi), to work

     7 # more broadly.  In particular, it no longer assumes ld accepts -zdefs.

     8 # This caused a restructing of the code, but the functionality has only

     9 # changed a little.

    11 dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])

    12 dnl

    13 dnl @summary figure out how to build C programs using POSIX threads

    14 dnl

    15 dnl This macro figures out how to build C programs using POSIX threads.

    16 dnl It sets the PTHREAD_LIBS output variable to the threads library and

    17 dnl linker flags, and the PTHREAD_CFLAGS output variable to any special

    18 dnl C compiler flags that are needed. (The user can also force certain

    19 dnl compiler flags/libs to be tested by setting these environment

    20 dnl variables.)

    21 dnl

    22 dnl Also sets PTHREAD_CC to any special C compiler that is needed for

    23 dnl multi-threaded programs (defaults to the value of CC otherwise).

    24 dnl (This is necessary on AIX to use the special cc_r compiler alias.)

    25 dnl

    26 dnl NOTE: You are assumed to not only compile your program with these

    27 dnl flags, but also link it with them as well. e.g. you should link

    28 dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS

    29 dnl $LIBS

    30 dnl

    31 dnl If you are only building threads programs, you may wish to use

    32 dnl these variables in your default LIBS, CFLAGS, and CC:

    33 dnl

    34 dnl        LIBS="$PTHREAD_LIBS $LIBS"

    35 dnl        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

    36 dnl        CC="$PTHREAD_CC"

    37 dnl

    38 dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute

    39 dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to

    40 dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).

    41 dnl

    42 dnl ACTION-IF-FOUND is a list of shell commands to run if a threads

    43 dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to

    44 dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the

    45 dnl default action will define HAVE_PTHREAD.

    46 dnl

    47 dnl Please let the authors know if this macro fails on any platform, or

    48 dnl if you have any other suggestions or comments. This macro was based

    49 dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with

    50 dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros

    51 dnl posted by Alejandro Forero Cuervo to the autoconf macro repository.

    52 dnl We are also grateful for the helpful feedback of numerous users.

    53 dnl

    54 dnl @category InstalledPackages

    55 dnl @author Steven G. Johnson <stevenj@alum.mit.edu>

    56 dnl @version 2006-05-29

    57 dnl @license GPLWithACException

    58 dnl

    59 dnl Checks for GCC shared/pthread inconsistency based on work by

    60 dnl Marcin Owsiany <marcin@owsiany.pl>

    63 AC_DEFUN([ACX_PTHREAD], [

    64 AC_REQUIRE([AC_CANONICAL_HOST])

    65 AC_LANG_SAVE

    66 AC_LANG_C

    67 acx_pthread_ok=no

    69 # We used to check for pthread.h first, but this fails if pthread.h

    70 # requires special compiler flags (e.g. on True64 or Sequent).

    71 # It gets checked for in the link test anyway.

    73 # First of all, check if the user has set any of the PTHREAD_LIBS,

    74 # etcetera environment variables, and if threads linking works using

    75 # them:

    76 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then

    77         save_CFLAGS="$CFLAGS"

    78         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

    79         save_LIBS="$LIBS"

    80         LIBS="$PTHREAD_LIBS $LIBS"

    81         AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])

    82         AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)

    83         AC_MSG_RESULT($acx_pthread_ok)

    84         if test x"$acx_pthread_ok" = xno; then

    85                 PTHREAD_LIBS=""

    86                 PTHREAD_CFLAGS=""

    87         fi

    88         LIBS="$save_LIBS"

    89         CFLAGS="$save_CFLAGS"

    90 fi

    92 # We must check for the threads library under a number of different

    93 # names; the ordering is very important because some systems

    94 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the

    95 # libraries is broken (non-POSIX).

    97 # Create a list of thread flags to try.  Items starting with a "-" are

    98 # C compiler flags, and other items are library names, except for "none"

    99 # which indicates that we try without any flags at all, and "pthread-config"

   100 # which is a program returning the flags for the Pth emulation library.

   102 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"

   104 # The ordering *is* (sometimes) important.  Some notes on the

   105 # individual items follow:

   107 # pthreads: AIX (must check this before -lpthread)

   108 # none: in case threads are in libc; should be tried before -Kthread and

   109 #       other compiler flags to prevent continual compiler warnings

   110 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)

   111 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)

   112 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)

   113 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)

   114 # -pthreads: Solaris/gcc

   115 # -mthreads: Mingw32/gcc, Lynx/gcc

   116 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it

   117 #      doesn't hurt to check since this sometimes defines pthreads too;

   118 #      also defines -D_REENTRANT)

   119 #      ... -mt is also the pthreads flag for HP/aCC

   120 # pthread: Linux, etcetera

   121 # --thread-safe: KAI C++

   122 # pthread-config: use pthread-config program (for GNU Pth library)

   124 case "${host_cpu}-${host_os}" in

   125         *solaris*)

   127         # On Solaris (at least, for some versions), libc contains stubbed

   128         # (non-functional) versions of the pthreads routines, so link-based

   129         # tests will erroneously succeed.  (We need to link with -pthreads/-mt/

   130         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather

   131         # a function called by this macro, so we could check for that, but

   132         # who knows whether they'll stub that too in a future libc.)  So,

   133         # we'll just look for -pthreads and -lpthread first:

   135         acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"

   136         ;;

   137 esac

   139 if test x"$acx_pthread_ok" = xno; then

   140 for flag in $acx_pthread_flags; do

   142         case $flag in

   143                 none)

   144                 AC_MSG_CHECKING([whether pthreads work without any flags])

   145                 ;;

   147                 -*)

   148                 AC_MSG_CHECKING([whether pthreads work with $flag])

   149                 PTHREAD_CFLAGS="$flag"

   150                 ;;

   152 		pthread-config)

   153 		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)

   154 		if test x"$acx_pthread_config" = xno; then continue; fi

   155 		PTHREAD_CFLAGS="`pthread-config --cflags`"

   156 		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"

   157 		;;

   159                 *)

   160                 AC_MSG_CHECKING([for the pthreads library -l$flag])

   161                 PTHREAD_LIBS="-l$flag"

   162                 ;;

   163         esac

   165         save_LIBS="$LIBS"

   166         save_CFLAGS="$CFLAGS"

   167         LIBS="$PTHREAD_LIBS $LIBS"

   168         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

   170         # Check for various functions.  We must include pthread.h,

   171         # since some functions may be macros.  (On the Sequent, we

   172         # need a special flag -Kthread to make this header compile.)

   173         # We check for pthread_join because it is in -lpthread on IRIX

   174         # while pthread_create is in libc.  We check for pthread_attr_init

   175         # due to DEC craziness with -lpthreads.  We check for

   176         # pthread_cleanup_push because it is one of the few pthread

   177         # functions on Solaris that doesn't have a non-functional libc stub.

   178         # We try pthread_create on general principles.

   179         AC_TRY_LINK([#include <pthread.h>],

   180                     [pthread_t th; pthread_join(th, 0);

   181                      pthread_attr_init(0); pthread_cleanup_push(0, 0);

   182                      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],

   183                     [acx_pthread_ok=yes])

   185         LIBS="$save_LIBS"

   186         CFLAGS="$save_CFLAGS"

   188         AC_MSG_RESULT($acx_pthread_ok)

   189         if test "x$acx_pthread_ok" = xyes; then

   190                 break;

   191         fi

   193         PTHREAD_LIBS=""

   194         PTHREAD_CFLAGS=""

   195 done

   196 fi

   198 # Various other checks:

   199 if test "x$acx_pthread_ok" = xyes; then

   200         save_LIBS="$LIBS"

   201         LIBS="$PTHREAD_LIBS $LIBS"

   202         save_CFLAGS="$CFLAGS"

   203         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

   205         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.

   206 	AC_MSG_CHECKING([for joinable pthread attribute])

   207 	attr_name=unknown

   208 	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do

   209 	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],

   210                         [attr_name=$attr; break])

   211 	done

   212         AC_MSG_RESULT($attr_name)

   213         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then

   214             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,

   215                                [Define to necessary symbol if this constant

   216                                 uses a non-standard name on your system.])

   217         fi

   219         AC_MSG_CHECKING([if more special flags are required for pthreads])

   220         flag=no

   221         case "${host_cpu}-${host_os}" in

   222             *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;

   223             *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;

   224         esac

   225         AC_MSG_RESULT(${flag})

   226         if test "x$flag" != xno; then

   227             PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"

   228         fi

   230         LIBS="$save_LIBS"

   231         CFLAGS="$save_CFLAGS"

   232         # More AIX lossage: must compile with xlc_r or cc_r

   233 	if test x"$GCC" != xyes; then

   234           AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})

   235         else

   236           PTHREAD_CC=$CC

   237 	fi

   239 	# The next part tries to detect GCC inconsistency with -shared on some

   240 	# architectures and systems. The problem is that in certain

   241 	# configurations, when -shared is specified, GCC "forgets" to

   242 	# internally use various flags which are still necessary.

   244 	#

   245 	# Prepare the flags

   246 	#

   247 	save_CFLAGS="$CFLAGS"

   248 	save_LIBS="$LIBS"

   249 	save_CC="$CC"

   251 	# Try with the flags determined by the earlier checks.

   252 	#

   253 	# -Wl,-z,defs forces link-time symbol resolution, so that the

   254 	# linking checks with -shared actually have any value

   255 	#

   256 	# FIXME: -fPIC is required for -shared on many architectures,

   257 	# so we specify it here, but the right way would probably be to

   258 	# properly detect whether it is actually required.

   259 	CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS"

   260 	LIBS="$PTHREAD_LIBS $LIBS"

   261 	CC="$PTHREAD_CC"

   263 	# In order not to create several levels of indentation, we test

   264 	# the value of "$done" until we find the cure or run out of ideas.

   265 	done="no"

   267 	# First, make sure the CFLAGS we added are actually accepted by our

   268 	# compiler.  If not (and OS X's ld, for instance, does not accept -z),

   269 	# then we can't do this test.

   270 	if test x"$done" = xno; then

   271 	   AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])

   272 	   AC_TRY_LINK(,, , [done=yes])

   274 	   if test "x$done" = xyes ; then

   275 	      AC_MSG_RESULT([no])

   276 	   else

   277 	      AC_MSG_RESULT([yes])

   278 	   fi

   279 	fi

   281 	if test x"$done" = xno; then

   282 	   AC_MSG_CHECKING([whether -pthread is sufficient with -shared])

   283 	   AC_TRY_LINK([#include <pthread.h>],

   284 	      [pthread_t th; pthread_join(th, 0);

   285 	      pthread_attr_init(0); pthread_cleanup_push(0, 0);

   286 	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],

   287 	      [done=yes])

   289 	   if test "x$done" = xyes; then

   290 	      AC_MSG_RESULT([yes])

   291 	   else

   292 	      AC_MSG_RESULT([no])

   293 	   fi

   294 	fi

   296 	#

   297 	# Linux gcc on some architectures such as mips/mipsel forgets

   298 	# about -lpthread

   299 	#

   300 	if test x"$done" = xno; then

   301 	   AC_MSG_CHECKING([whether -lpthread fixes that])

   302 	   LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"

   303 	   AC_TRY_LINK([#include <pthread.h>],

   304 	      [pthread_t th; pthread_join(th, 0);

   305 	      pthread_attr_init(0); pthread_cleanup_push(0, 0);

   306 	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],

   307 	      [done=yes])

   309 	   if test "x$done" = xyes; then

   310 	      AC_MSG_RESULT([yes])

   311 	      PTHREAD_LIBS="-lpthread $PTHREAD_LIBS"

   312 	   else

   313 	      AC_MSG_RESULT([no])

   314 	   fi

   315 	fi

   316 	#

   317 	# FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc

   318 	#

   319 	if test x"$done" = xno; then

   320 	   AC_MSG_CHECKING([whether -lc_r fixes that])

   321 	   LIBS="-lc_r $PTHREAD_LIBS $save_LIBS"

   322 	   AC_TRY_LINK([#include <pthread.h>],

   323 	       [pthread_t th; pthread_join(th, 0);

   324 	        pthread_attr_init(0); pthread_cleanup_push(0, 0);

   325 	        pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],

   326 	       [done=yes])

   328 	   if test "x$done" = xyes; then

   329 	      AC_MSG_RESULT([yes])

   330 	      PTHREAD_LIBS="-lc_r $PTHREAD_LIBS"

   331 	   else

   332 	      AC_MSG_RESULT([no])

   333 	   fi

   334 	fi

   335 	if test x"$done" = xno; then

   336 	   # OK, we have run out of ideas

   337 	   AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries])

   339 	   # so it's not safe to assume that we may use pthreads

   340 	   acx_pthread_ok=no

   341 	fi

   343 	CFLAGS="$save_CFLAGS"

   344 	LIBS="$save_LIBS"

   345 	CC="$save_CC"

   346 else

   347         PTHREAD_CC="$CC"

   348 fi

   350 AC_SUBST(PTHREAD_LIBS)

   351 AC_SUBST(PTHREAD_CFLAGS)

   352 AC_SUBST(PTHREAD_CC)

   354 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:

   355 if test x"$acx_pthread_ok" = xyes; then

   356         ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])

   357         :

   358 else

   359         acx_pthread_ok=no

   360         $2

   361 fi

   362 AC_LANG_RESTORE

   363 ])dnl ACX_PTHREAD

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