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1# ===========================================================================
2#           http://www.nongnu.org/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#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
37#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
38#   is not found. If ACTION-IF-FOUND is not specified, the default action
39#   will define HAVE_PTHREAD.
40#
41#   Please let the authors know if this macro fails on any platform, or if
42#   you have any other suggestions or comments. This macro was based on work
43#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
44#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
45#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
46#   grateful for the helpful feedback of numerous users.
47#
48# LICENSE
49#
50#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
51#
52#   This program is free software: you can redistribute it and/or modify it
53#   under the terms of the GNU General Public License as published by the
54#   Free Software Foundation, either version 3 of the License, or (at your
55#   option) any later version.
56#
57#   This program is distributed in the hope that it will be useful, but
58#   WITHOUT ANY WARRANTY; without even the implied warranty of
59#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
60#   Public License for more details.
61#
62#   You should have received a copy of the GNU General Public License along
63#   with this program. If not, see <http://www.gnu.org/licenses/>.
64#
65#   As a special exception, the respective Autoconf Macro's copyright owner
66#   gives unlimited permission to copy, distribute and modify the configure
67#   scripts that are the output of Autoconf when processing the Macro. You
68#   need not follow the terms of the GNU General Public License when using
69#   or distributing such scripts, even though portions of the text of the
70#   Macro appear in them. The GNU General Public License (GPL) does govern
71#   all other use of the material that constitutes the Autoconf Macro.
72#
73#   This special exception to the GPL applies to versions of the Autoconf
74#   Macro released by the Autoconf Archive. When you make and distribute a
75#   modified version of the Autoconf Macro, you may extend this special
76#   exception to the GPL to apply to your modified version as well.
77
78#serial 6
79
80AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
81AC_DEFUN([AX_PTHREAD], [
82AC_REQUIRE([AC_CANONICAL_HOST])
83AC_LANG_SAVE
84AC_LANG_C
85ax_pthread_ok=no
86
87# We used to check for pthread.h first, but this fails if pthread.h
88# requires special compiler flags (e.g. on True64 or Sequent).
89# It gets checked for in the link test anyway.
90
91# First of all, check if the user has set any of the PTHREAD_LIBS,
92# etcetera environment variables, and if threads linking works using
93# them:
94if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
95        save_CFLAGS="$CFLAGS"
96        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
97        save_LIBS="$LIBS"
98        LIBS="$PTHREAD_LIBS $LIBS"
99        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
100        AC_TRY_LINK_FUNC(pthread_join, ax_pthread_ok=yes)
101        AC_MSG_RESULT($ax_pthread_ok)
102        if test x"$ax_pthread_ok" = xno; then
103                PTHREAD_LIBS=""
104                PTHREAD_CFLAGS=""
105        fi
106        LIBS="$save_LIBS"
107        CFLAGS="$save_CFLAGS"
108fi
109
110# We must check for the threads library under a number of different
111# names; the ordering is very important because some systems
112# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
113# libraries is broken (non-POSIX).
114
115# Create a list of thread flags to try.  Items starting with a "-" are
116# C compiler flags, and other items are library names, except for "none"
117# which indicates that we try without any flags at all, and "pthread-config"
118# which is a program returning the flags for the Pth emulation library.
119
120ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
121
122# The ordering *is* (sometimes) important.  Some notes on the
123# individual items follow:
124
125# pthreads: AIX (must check this before -lpthread)
126# none: in case threads are in libc; should be tried before -Kthread and
127#       other compiler flags to prevent continual compiler warnings
128# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
129# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
130# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
131# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
132# -pthreads: Solaris/gcc
133# -mthreads: Mingw32/gcc, Lynx/gcc
134# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
135#      doesn't hurt to check since this sometimes defines pthreads too;
136#      also defines -D_REENTRANT)
137#      ... -mt is also the pthreads flag for HP/aCC
138# pthread: Linux, etcetera
139# --thread-safe: KAI C++
140# pthread-config: use pthread-config program (for GNU Pth library)
141
142case "${host_cpu}-${host_os}" in
143        *solaris*)
144
145        # On Solaris (at least, for some versions), libc contains stubbed
146        # (non-functional) versions of the pthreads routines, so link-based
147        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
148        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
149        # a function called by this macro, so we could check for that, but
150        # who knows whether they'll stub that too in a future libc.)  So,
151        # we'll just look for -pthreads and -lpthread first:
152
153        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
154        ;;
155
156	*-darwin*)
157	acx_pthread_flags="-pthread $acx_pthread_flags"
158	;;
159esac
160
161if test x"$ax_pthread_ok" = xno; then
162for flag in $ax_pthread_flags; do
163
164        case $flag in
165                none)
166                AC_MSG_CHECKING([whether pthreads work without any flags])
167                ;;
168
169                -*)
170                AC_MSG_CHECKING([whether pthreads work with $flag])
171                PTHREAD_CFLAGS="$flag"
172                ;;
173
174		pthread-config)
175		AC_CHECK_PROG(ax_pthread_config, pthread-config, yes, no)
176		if test x"$ax_pthread_config" = xno; then continue; fi
177		PTHREAD_CFLAGS="`pthread-config --cflags`"
178		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
179		;;
180
181                *)
182                AC_MSG_CHECKING([for the pthreads library -l$flag])
183                PTHREAD_LIBS="-l$flag"
184                ;;
185        esac
186
187        save_LIBS="$LIBS"
188        save_CFLAGS="$CFLAGS"
189        LIBS="$PTHREAD_LIBS $LIBS"
190        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
191
192        # Check for various functions.  We must include pthread.h,
193        # since some functions may be macros.  (On the Sequent, we
194        # need a special flag -Kthread to make this header compile.)
195        # We check for pthread_join because it is in -lpthread on IRIX
196        # while pthread_create is in libc.  We check for pthread_attr_init
197        # due to DEC craziness with -lpthreads.  We check for
198        # pthread_cleanup_push because it is one of the few pthread
199        # functions on Solaris that doesn't have a non-functional libc stub.
200        # We try pthread_create on general principles.
201        AC_TRY_LINK([#include <pthread.h>
202	             static void routine(void* a) {a=0;}
203	             static void* start_routine(void* a) {return a;}],
204                    [pthread_t th; pthread_attr_t attr;
205                     pthread_join(th, 0);
206                     pthread_attr_init(&attr);
207                     pthread_cleanup_push(routine, 0);
208                     pthread_create(&th,0,start_routine,0);
209                     pthread_cleanup_pop(0); ],
210                    [ax_pthread_ok=yes])
211
212        LIBS="$save_LIBS"
213        CFLAGS="$save_CFLAGS"
214
215        AC_MSG_RESULT($ax_pthread_ok)
216        if test "x$ax_pthread_ok" = xyes; then
217                break;
218        fi
219
220        PTHREAD_LIBS=""
221        PTHREAD_CFLAGS=""
222done
223fi
224
225# Various other checks:
226if test "x$ax_pthread_ok" = xyes; then
227        save_LIBS="$LIBS"
228        LIBS="$PTHREAD_LIBS $LIBS"
229        save_CFLAGS="$CFLAGS"
230        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
231
232        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
233	AC_MSG_CHECKING([for joinable pthread attribute])
234	attr_name=unknown
235	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
236	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
237                        [attr_name=$attr; break])
238	done
239        AC_MSG_RESULT($attr_name)
240        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
241            AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
242                               [Define to necessary symbol if this constant
243                                uses a non-standard name on your system.])
244        fi
245
246        AC_MSG_CHECKING([if more special flags are required for pthreads])
247        flag=no
248        case "${host_cpu}-${host_os}" in
249            *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
250            *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
251        esac
252        AC_MSG_RESULT(${flag})
253        if test "x$flag" != xno; then
254            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
255        fi
256
257        LIBS="$save_LIBS"
258        CFLAGS="$save_CFLAGS"
259
260        # More AIX lossage: must compile with xlc_r or cc_r
261	if test x"$GCC" != xyes; then
262          AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
263        else
264          PTHREAD_CC=$CC
265	fi
266else
267        PTHREAD_CC="$CC"
268fi
269
270AC_SUBST(PTHREAD_LIBS)
271AC_SUBST(PTHREAD_CFLAGS)
272AC_SUBST(PTHREAD_CC)
273
274# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
275if test x"$ax_pthread_ok" = xyes; then
276        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
277        :
278else
279        ax_pthread_ok=no
280        $2
281fi
282AC_LANG_RESTORE
283])dnl AX_PTHREAD