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/Unittests/googletest/m4/acx_pthread.m4

http://unladen-swallow.googlecode.com/
m4 | 363 lines | 231 code | 42 blank | 90 comment | 0 complexity | bc44b96a832f4b425b90f8fddf2d0eee MD5 | raw file
  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.
 10
 11dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
 12dnl
 13dnl @summary figure out how to build C programs using POSIX threads
 14dnl
 15dnl This macro figures out how to build C programs using POSIX threads.
 16dnl It sets the PTHREAD_LIBS output variable to the threads library and
 17dnl linker flags, and the PTHREAD_CFLAGS output variable to any special
 18dnl C compiler flags that are needed. (The user can also force certain
 19dnl compiler flags/libs to be tested by setting these environment
 20dnl variables.)
 21dnl
 22dnl Also sets PTHREAD_CC to any special C compiler that is needed for
 23dnl multi-threaded programs (defaults to the value of CC otherwise).
 24dnl (This is necessary on AIX to use the special cc_r compiler alias.)
 25dnl
 26dnl NOTE: You are assumed to not only compile your program with these
 27dnl flags, but also link it with them as well. e.g. you should link
 28dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS
 29dnl $LIBS
 30dnl
 31dnl If you are only building threads programs, you may wish to use
 32dnl these variables in your default LIBS, CFLAGS, and CC:
 33dnl
 34dnl        LIBS="$PTHREAD_LIBS $LIBS"
 35dnl        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
 36dnl        CC="$PTHREAD_CC"
 37dnl
 38dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
 39dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
 40dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
 41dnl
 42dnl ACTION-IF-FOUND is a list of shell commands to run if a threads
 43dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to
 44dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the
 45dnl default action will define HAVE_PTHREAD.
 46dnl
 47dnl Please let the authors know if this macro fails on any platform, or
 48dnl if you have any other suggestions or comments. This macro was based
 49dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with
 50dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros
 51dnl posted by Alejandro Forero Cuervo to the autoconf macro repository.
 52dnl We are also grateful for the helpful feedback of numerous users.
 53dnl
 54dnl @category InstalledPackages
 55dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
 56dnl @version 2006-05-29
 57dnl @license GPLWithACException
 58dnl 
 59dnl Checks for GCC shared/pthread inconsistency based on work by
 60dnl Marcin Owsiany <marcin@owsiany.pl>
 61
 62
 63AC_DEFUN([ACX_PTHREAD], [
 64AC_REQUIRE([AC_CANONICAL_HOST])
 65AC_LANG_SAVE
 66AC_LANG_C
 67acx_pthread_ok=no
 68
 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.
 72
 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:
 76if 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="$save_CFLAGS"
 90fi
 91
 92# We must check for the threads library under a number of different
 93# names; the ordering is very important because some systems
 94# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
 95# libraries is broken (non-POSIX).
 96
 97# Create a list of thread flags to try.  Items starting with a "-" are
 98# C compiler flags, and other items are library names, except for "none"
 99# which indicates that we try without any flags at all, and "pthread-config"
100# which is a program returning the flags for the Pth emulation library.
101
102acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
103
104# The ordering *is* (sometimes) important.  Some notes on the
105# individual items follow:
106
107# pthreads: AIX (must check this before -lpthread)
108# none: in case threads are in libc; should be tried before -Kthread and
109#       other compiler flags to prevent continual compiler warnings
110# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
111# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
112# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
113# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
114# -pthreads: Solaris/gcc
115# -mthreads: Mingw32/gcc, Lynx/gcc
116# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
117#      doesn't hurt to check since this sometimes defines pthreads too;
118#      also defines -D_REENTRANT)
119#      ... -mt is also the pthreads flag for HP/aCC
120# pthread: Linux, etcetera
121# --thread-safe: KAI C++
122# pthread-config: use pthread-config program (for GNU Pth library)
123
124case "${host_cpu}-${host_os}" in
125        *solaris*)
126
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:
134
135        acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
136        ;;
137esac
138
139if test x"$acx_pthread_ok" = xno; then
140for flag in $acx_pthread_flags; do
141
142        case $flag in
143                none)
144                AC_MSG_CHECKING([whether pthreads work without any flags])
145                ;;
146
147                -*)
148                AC_MSG_CHECKING([whether pthreads work with $flag])
149                PTHREAD_CFLAGS="$flag"
150                ;;
151
152		pthread-config)
153		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
154		if test x"$acx_pthread_config" = xno; then continue; fi
155		PTHREAD_CFLAGS="`pthread-config --cflags`"
156		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
157		;;
158
159                *)
160                AC_MSG_CHECKING([for the pthreads library -l$flag])
161                PTHREAD_LIBS="-l$flag"
162                ;;
163        esac
164
165        save_LIBS="$LIBS"
166        save_CFLAGS="$CFLAGS"
167        LIBS="$PTHREAD_LIBS $LIBS"
168        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
169
170        # Check for various functions.  We must include pthread.h,
171        # since some functions may be macros.  (On the Sequent, we
172        # need a special flag -Kthread to make this header compile.)
173        # We check for pthread_join because it is in -lpthread on IRIX
174        # while pthread_create is in libc.  We check for pthread_attr_init
175        # due to DEC craziness with -lpthreads.  We check for
176        # pthread_cleanup_push because it is one of the few pthread
177        # functions on Solaris that doesn't have a non-functional libc stub.
178        # We try pthread_create on general principles.
179        AC_TRY_LINK([#include <pthread.h>],
180                    [pthread_t th; pthread_join(th, 0);
181                     pthread_attr_init(0); pthread_cleanup_push(0, 0);
182                     pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
183                    [acx_pthread_ok=yes])
184
185        LIBS="$save_LIBS"
186        CFLAGS="$save_CFLAGS"
187
188        AC_MSG_RESULT($acx_pthread_ok)
189        if test "x$acx_pthread_ok" = xyes; then
190                break;
191        fi
192
193        PTHREAD_LIBS=""
194        PTHREAD_CFLAGS=""
195done
196fi
197
198# Various other checks:
199if test "x$acx_pthread_ok" = xyes; then
200        save_LIBS="$LIBS"
201        LIBS="$PTHREAD_LIBS $LIBS"
202        save_CFLAGS="$CFLAGS"
203        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
204
205        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
206	AC_MSG_CHECKING([for joinable pthread attribute])
207	attr_name=unknown
208	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
209	    AC_TRY_LINK([#include <pthread.h>], [int attr=$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, $attr_name,
215                               [Define to necessary symbol if this constant
216                                uses a non-standard name on your system.])
217        fi
218
219        AC_MSG_CHECKING([if more special flags are required for pthreads])
220        flag=no
221        case "${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 $PTHREAD_CFLAGS"
228        fi
229
230        LIBS="$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
238
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.
243	
244	#
245	# Prepare the flags
246	#
247	save_CFLAGS="$CFLAGS"
248	save_LIBS="$LIBS"
249	save_CC="$CC"
250	
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"
262	
263	# In order not to create several levels of indentation, we test
264	# the value of "$done" until we find the cure or run out of ideas.
265	done="no"
266	
267	# First, make sure the CFLAGS we added are actually accepted by our
268	# compiler.  If not (and OS X's ld, for instance, does not accept -z),
269	# then we can't do this test.
270	if test x"$done" = xno; then
271	   AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])
272	   AC_TRY_LINK(,, , [done=yes])
273	
274	   if test "x$done" = xyes ; then
275	      AC_MSG_RESULT([no])
276	   else
277	      AC_MSG_RESULT([yes])
278	   fi
279	fi
280	
281	if test x"$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])
288	   
289	   if test "x$done" = xyes; then
290	      AC_MSG_RESULT([yes])
291	   else
292	      AC_MSG_RESULT([no])
293	   fi
294	fi
295	
296	#
297	# Linux gcc on some architectures such as mips/mipsel forgets
298	# about -lpthread
299	#
300	if test x"$done" = xno; then
301	   AC_MSG_CHECKING([whether -lpthread fixes that])
302	   LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"
303	   AC_TRY_LINK([#include <pthread.h>],
304	      [pthread_t th; pthread_join(th, 0);
305	      pthread_attr_init(0); pthread_cleanup_push(0, 0);
306	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
307	      [done=yes])
308	
309	   if test "x$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 $save_LIBS"
322	   AC_TRY_LINK([#include <pthread.h>],
323	       [pthread_t th; pthread_join(th, 0);
324	        pthread_attr_init(0); pthread_cleanup_push(0, 0);
325	        pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
326	       [done=yes])
327	
328	   if test "x$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])
338	
339	   # so it's not safe to assume that we may use pthreads
340	   acx_pthread_ok=no
341	fi
342	
343	CFLAGS="$save_CFLAGS"
344	LIBS="$save_LIBS"
345	CC="$save_CC"
346else
347        PTHREAD_CC="$CC"
348fi
349
350AC_SUBST(PTHREAD_LIBS)
351AC_SUBST(PTHREAD_CFLAGS)
352AC_SUBST(PTHREAD_CC)
353
354# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
355if 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        :
358else
359        acx_pthread_ok=no
360        $2
361fi
362AC_LANG_RESTORE
363])dnl ACX_PTHREAD