1##### http://autoconf-archive.cryp.to/acx_pthread.html
2#
3# SYNOPSIS
4#
5#   ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
6#
7# DESCRIPTION
8#
9#   This macro figures out how to build C programs using POSIX threads.
10#   It sets the PTHREAD_LIBS output variable to the threads library and
11#   linker flags, and the PTHREAD_CFLAGS output variable to any special
12#   C compiler flags that are needed. (The user can also force certain
13#   compiler flags/libs to be tested by setting these environment
14#   variables.)
15#
16#   Also sets PTHREAD_CC to any special C compiler that is needed for
17#   multi-threaded programs (defaults to the value of CC otherwise).
18#   (This is necessary on AIX to use the special cc_r compiler alias.)
19#
20#   NOTE: You are assumed to not only compile your program with these
21#   flags, but also link it with them as well. e.g. you should link
22#   with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS
23#   $LIBS
24#
25#   If you are only building threads programs, you may wish to use
26#   these variables in your default LIBS, CFLAGS, and CC:
27#
28#          LIBS="$PTHREAD_LIBS $LIBS"
29#          CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
30#          CC="$PTHREAD_CC"
31#
32#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
33#   constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
34#   that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
35#
36#   ACTION-IF-FOUND is a list of shell commands to run if a threads
37#   library is found, and ACTION-IF-NOT-FOUND is a list of commands to
38#   run it if it is not found. If ACTION-IF-FOUND is not specified, the
39#   default action will define HAVE_PTHREAD.
40#
41#   Please let the authors know if this macro fails on any platform, or
42#   if you have any other suggestions or comments. This macro was based
43#   on work by SGJ on autoconf scripts for FFTW (http://www.fftw.org/)
44#   (with help from M. Frigo), as well as ac_pthread and hb_pthread
45#   macros posted by Alejandro Forero Cuervo to the autoconf macro
46#   repository. We are also grateful for the helpful feedback of
47#   numerous users.
48#
49# LAST MODIFICATION
50#
51#   2006-05-29
52#
53# COPYLEFT
54#
55#   Copyright (c) 2006 Steven G. Johnson <stevenj@alum.mit.edu>
56#
57#   This program is free software; you can redistribute it and/or
58#   modify it under the terms of the GNU General Public License as
59#   published by the Free Software Foundation; either version 2 of the
60#   License, or (at your option) any later version.
61#
62#   This program is distributed in the hope that it will be useful, but
63#   WITHOUT ANY WARRANTY; without even the implied warranty of
64#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
65#   General Public License for more details.
66#
67#   You should have received a copy of the GNU General Public License
68#   along with this program; if not, write to the Free Software
69#   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
70#   02111-1307, USA.
71#
72#   As a special exception, the respective Autoconf Macro's copyright
73#   owner gives unlimited permission to copy, distribute and modify the
74#   configure scripts that are the output of Autoconf when processing
75#   the Macro. You need not follow the terms of the GNU General Public
76#   License when using or distributing such scripts, even though
77#   portions of the text of the Macro appear in them. The GNU General
78#   Public License (GPL) does govern all other use of the material that
79#   constitutes the Autoconf Macro.
80#
81#   This special exception to the GPL applies to versions of the
82#   Autoconf Macro released by the Autoconf Macro Archive. When you
83#   make and distribute a modified version of the Autoconf Macro, you
84#   may extend this special exception to the GPL to apply to your
85#   modified version as well.
86
87AC_DEFUN([ACX_PTHREAD], [
88AC_REQUIRE([AC_CANONICAL_HOST])
89AC_LANG_SAVE
90AC_LANG_C
91acx_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:
100if 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=$PTHREAD_CFLAGS])
106        AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
107        AC_MSG_RESULT($acx_pthread_ok)
108        if test x"$acx_pthread_ok" = xno; then
109                PTHREAD_LIBS=""
110                PTHREAD_CFLAGS=""
111        fi
112        LIBS="$save_LIBS"
113        CFLAGS="$save_CFLAGS"
114fi
115
116# We must check for the threads library under a number of different
117# names; the ordering is very important because some systems
118# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
119# libraries is broken (non-POSIX).
120
121# Create a list of thread flags to try.  Items starting with a "-" are
122# C compiler flags, and other items are library names, except for "none"
123# which indicates that we try without any flags at all, and "pthread-config"
124# which is a program returning the flags for the Pth emulation library.
125
126acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
127
128# The ordering *is* (sometimes) important.  Some notes on the
129# individual items follow:
130
131# pthreads: AIX (must check this before -lpthread)
132# none: in case threads are in libc; should be tried before -Kthread and
133#       other compiler flags to prevent continual compiler warnings
134# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
135# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
136# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
137# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
138# -pthreads: Solaris/gcc
139# -mthreads: Mingw32/gcc, Lynx/gcc
140# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
141#      doesn't hurt to check since this sometimes defines pthreads too;
142#      also defines -D_REENTRANT)
143#      ... -mt is also the pthreads flag for HP/aCC
144# pthread: Linux, etcetera
145# --thread-safe: KAI C++
146# pthread-config: use pthread-config program (for GNU Pth library)
147
148case "${host_cpu}-${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        acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
160        ;;
161esac
162
163if test x"$acx_pthread_ok" = xno; then
164for flag in $acx_pthread_flags; do
165
166        case $flag in
167                none)
168                AC_MSG_CHECKING([whether pthreads work without any flags])
169                ;;
170
171                -*)
172                AC_MSG_CHECKING([whether pthreads work with $flag])
173                PTHREAD_CFLAGS="$flag"
174                ;;
175
176		pthread-config)
177		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
178		if test x"$acx_pthread_config" = xno; then continue; fi
179		PTHREAD_CFLAGS="`pthread-config --cflags`"
180		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
181		;;
182
183                *)
184                AC_MSG_CHECKING([for the pthreads library -l$flag])
185                PTHREAD_LIBS="-l$flag"
186                ;;
187        esac
188
189        save_LIBS="$LIBS"
190        save_CFLAGS="$CFLAGS"
191        LIBS="$PTHREAD_LIBS $LIBS"
192        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
193
194        # Check for various functions.  We must include pthread.h,
195        # since some functions may be macros.  (On the Sequent, we
196        # need a special flag -Kthread to make this header compile.)
197        # We check for pthread_join because it is in -lpthread on IRIX
198        # while pthread_create is in libc.  We check for pthread_attr_init
199        # due to DEC craziness with -lpthreads.  We check for
200        # pthread_cleanup_push because it is one of the few pthread
201        # functions on Solaris that doesn't have a non-functional libc stub.
202        # We try pthread_create on general principles.
203        AC_TRY_LINK([#include <pthread.h>],
204                    [pthread_t th; pthread_join(th, 0);
205                     pthread_attr_init(0); pthread_cleanup_push(0, 0);
206                     pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
207                    [acx_pthread_ok=yes])
208
209        LIBS="$save_LIBS"
210        CFLAGS="$save_CFLAGS"
211
212        AC_MSG_RESULT($acx_pthread_ok)
213        if test "x$acx_pthread_ok" = xyes; then
214                break;
215        fi
216
217        PTHREAD_LIBS=""
218        PTHREAD_CFLAGS=""
219done
220fi
221
222# Various other checks:
223if test "x$acx_pthread_ok" = xyes; then
224        save_LIBS="$LIBS"
225        LIBS="$PTHREAD_LIBS $LIBS"
226        save_CFLAGS="$CFLAGS"
227        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
228
229        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
230	AC_MSG_CHECKING([for joinable pthread attribute])
231	attr_name=unknown
232	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
233	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
234                        [attr_name=$attr; break])
235	done
236        AC_MSG_RESULT($attr_name)
237        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
238            AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
239                               [Define to necessary symbol if this constant
240                                uses a non-standard name on your system.])
241        fi
242
243        AC_MSG_CHECKING([if more special flags are required for pthreads])
244        flag=no
245        case "${host_cpu}-${host_os}" in
246            *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
247            *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
248        esac
249        AC_MSG_RESULT(${flag})
250        if test "x$flag" != xno; then
251            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
252        fi
253
254        LIBS="$save_LIBS"
255        CFLAGS="$save_CFLAGS"
256
257        # More AIX lossage: must compile with xlc_r or cc_r
258	if test x"$GCC" != xyes; then
259          AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
260        else
261          PTHREAD_CC=$CC
262	fi
263else
264        PTHREAD_CC="$CC"
265fi
266
267AC_SUBST(PTHREAD_LIBS)
268AC_SUBST(PTHREAD_CFLAGS)
269AC_SUBST(PTHREAD_CC)
270
271# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
272if test x"$acx_pthread_ok" = xyes; then
273        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
274        :
275else
276        acx_pthread_ok=no
277        $2
278fi
279AC_LANG_RESTORE
280])dnl ACX_PTHREAD
281