1# ===========================================================================
2#              http://autoconf-archive.cryp.to/acx_pthread.html
3# ===========================================================================
4#
5# SYNOPSIS
6#
7#   ACX_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#   NOTE: You are assumed to not only compile your program with these flags,
18#   but also link it with them as well. e.g. you should link with
19#   $CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
20#
21#   If you are only building threads programs, you may wish to use these
22#   variables in your default LIBS and CFLAGS:
23#
24#          LIBS="$PTHREAD_LIBS $LIBS"
25#          CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
26#
27#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
28#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
29#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
30#
31#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
32#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
33#   is not found. If ACTION-IF-FOUND is not specified, the default action
34#   will define HAVE_PTHREAD.
35#
36#   Please let the authors know if this macro fails on any platform, or if
37#   you have any other suggestions or comments. This macro was based on work
38#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
39#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
40#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
41#   grateful for the helpful feedback of numerous users.
42#
43# LAST MODIFICATION
44#
45#   2008-04-12
46#
47# COPYLEFT
48#
49#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
50#
51#   This program is free software: you can redistribute it and/or modify it
52#   under the terms of the GNU General Public License as published by the
53#   Free Software Foundation, either version 3 of the License, or (at your
54#   option) any later version.
55#
56#   This program is distributed in the hope that it will be useful, but
57#   WITHOUT ANY WARRANTY; without even the implied warranty of
58#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
59#   Public License for more details.
60#
61#   You should have received a copy of the GNU General Public License along
62#   with this program. If not, see <http://www.gnu.org/licenses/>.
63#
64#   As a special exception, the respective Autoconf Macro's copyright owner
65#   gives unlimited permission to copy, distribute and modify the configure
66#   scripts that are the output of Autoconf when processing the Macro. You
67#   need not follow the terms of the GNU General Public License when using
68#   or distributing such scripts, even though portions of the text of the
69#   Macro appear in them. The GNU General Public License (GPL) does govern
70#   all other use of the material that constitutes the Autoconf Macro.
71#
72#   This special exception to the GPL applies to versions of the Autoconf
73#   Macro released by the Autoconf Macro Archive. When you make and
74#   distribute a modified version of the Autoconf Macro, you may extend this
75#   special exception to the GPL to apply to your modified version as well.
76
77AC_DEFUN([ACX_PTHREAD], [
78AC_REQUIRE([AC_CANONICAL_HOST])
79acx_pthread_ok=no
80
81# We used to check for pthread.h first, but this fails if pthread.h
82# requires special compiler flags (e.g. on True64 or Sequent).
83# It gets checked for in the link test anyway.
84
85# First of all, check if the user has set any of the PTHREAD_LIBS,
86# etcetera environment variables, and if threads linking works using
87# them:
88if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
89        save_CFLAGS="$CFLAGS"
90        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
91        save_LIBS="$LIBS"
92        LIBS="$PTHREAD_LIBS $LIBS"
93        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
94        AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
95        AC_MSG_RESULT($acx_pthread_ok)
96        if test x"$acx_pthread_ok" = xno; then
97                PTHREAD_LIBS=""
98                PTHREAD_CFLAGS=""
99        fi
100        LIBS="$save_LIBS"
101        CFLAGS="$save_CFLAGS"
102fi
103
104# We must check for the threads library under a number of different
105# names; the ordering is very important because some systems
106# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
107# libraries is broken (non-POSIX).
108
109# Create a list of thread flags to try.  Items starting with a "-" are
110# C compiler flags, and other items are library names, except for "none"
111# which indicates that we try without any flags at all, and "pthread-config"
112# which is a program returning the flags for the Pth emulation library.
113
114acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
115
116# The ordering *is* (sometimes) important.  Some notes on the
117# individual items follow:
118
119# pthreads: AIX (must check this before -lpthread)
120# none: in case threads are in libc; should be tried before -Kthread and
121#       other compiler flags to prevent continual compiler warnings
122# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
123# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
124# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
125# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
126# -pthreads: Solaris/gcc
127# -mthreads: Mingw32/gcc, Lynx/gcc
128# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
129#      doesn't hurt to check since this sometimes defines pthreads too;
130#      also defines -D_REENTRANT)
131#      ... -mt is also the pthreads flag for HP/aCC
132# pthread: Linux, etcetera
133# --thread-safe: KAI C++
134# pthread-config: use pthread-config program (for GNU Pth library)
135
136case "${host_cpu}-${host_os}" in
137        *solaris*)
138
139        # On Solaris (at least, for some versions), libc contains stubbed
140        # (non-functional) versions of the pthreads routines, so link-based
141        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
142        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
143        # a function called by this macro, so we could check for that, but
144        # who knows whether they'll stub that too in a future libc.)  So,
145        # we'll just look for -pthreads and -lpthread first:
146
147        acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
148        ;;
149esac
150
151if test x"$acx_pthread_ok" = xno; then
152for flag in $acx_pthread_flags; do
153
154        case $flag in
155                none)
156                AC_MSG_CHECKING([whether pthreads work without any flags])
157                ;;
158
159                -*)
160                AC_MSG_CHECKING([whether pthreads work with $flag])
161                PTHREAD_CFLAGS="$flag"
162                PTHREAD_LIBS="$flag"
163                ;;
164
165		pthread-config)
166		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
167		if test x"$acx_pthread_config" = xno; then continue; fi
168		PTHREAD_CFLAGS="`pthread-config --cflags`"
169		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
170		;;
171
172                *)
173                AC_MSG_CHECKING([for the pthreads library -l$flag])
174                PTHREAD_LIBS="-l$flag"
175                ;;
176        esac
177
178        save_LIBS="$LIBS"
179        save_CFLAGS="$CFLAGS"
180        LIBS="$PTHREAD_LIBS $LIBS"
181        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
182
183        # Check for various functions.  We must include pthread.h,
184        # since some functions may be macros.  (On the Sequent, we
185        # need a special flag -Kthread to make this header compile.)
186        # We check for pthread_join because it is in -lpthread on IRIX
187        # while pthread_create is in libc.  We check for pthread_attr_init
188        # due to DEC craziness with -lpthreads.  We check for
189        # pthread_cleanup_push because it is one of the few pthread
190        # functions on Solaris that doesn't have a non-functional libc stub.
191        # We try pthread_create on general principles.
192        AC_TRY_LINK([#include <pthread.h>],
193                    [pthread_t th; pthread_join(th, 0);
194                     pthread_attr_init(0); pthread_cleanup_push(0, 0);
195                     pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
196                    [acx_pthread_ok=yes])
197
198        LIBS="$save_LIBS"
199        CFLAGS="$save_CFLAGS"
200
201        AC_MSG_RESULT($acx_pthread_ok)
202        if test "x$acx_pthread_ok" = xyes; then
203                break;
204        fi
205
206        PTHREAD_LIBS=""
207        PTHREAD_CFLAGS=""
208done
209fi
210
211# Various other checks:
212if test "x$acx_pthread_ok" = xyes; then
213        save_LIBS="$LIBS"
214        LIBS="$PTHREAD_LIBS $LIBS"
215        save_CFLAGS="$CFLAGS"
216        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
217
218        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
219	AC_MSG_CHECKING([for joinable pthread attribute])
220	attr_name=unknown
221	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
222	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
223                        [attr_name=$attr; break])
224	done
225        AC_MSG_RESULT($attr_name)
226        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
227            AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
228                               [Define to necessary symbol if this constant
229                                uses a non-standard name on your system.])
230        fi
231
232        AC_MSG_CHECKING([if more special flags are required for pthreads])
233        flag=no
234        case "${host_cpu}-${host_os}" in
235            *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
236            *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
237        esac
238        AC_MSG_RESULT(${flag})
239        if test "x$flag" != xno; then
240            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
241        fi
242
243        LIBS="$save_LIBS"
244        CFLAGS="$save_CFLAGS"
245fi
246
247AC_SUBST(PTHREAD_LIBS)
248AC_SUBST(PTHREAD_CFLAGS)
249
250# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
251if test x"$acx_pthread_ok" = xyes; then
252        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
253        :
254else
255        acx_pthread_ok=no
256        $2
257fi
258])
259