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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 # 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.
78 AC_DEFUN([ACX_PTHREAD], [
79 AC_REQUIRE([AC_CANONICAL_HOST])
80 AC_LANG_SAVE
81 AC_LANG_C
82 acx_pthread_ok=no
84 # We used to check for pthread.h first, but this fails if pthread.h
85 # requires special compiler flags (e.g. on True64 or Sequent).
86 # It gets checked for in the link test anyway.
88 # First of all, check if the user has set any of the PTHREAD_LIBS,
89 # etcetera environment variables, and if threads linking works using
90 # them:
91 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
92 save_CFLAGS="$CFLAGS"
93 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
94 save_LIBS="$LIBS"
95 LIBS="$PTHREAD_LIBS $LIBS"
96 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
97 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
98 AC_MSG_RESULT($acx_pthread_ok)
99 if test x"$acx_pthread_ok" = xno; then
100 PTHREAD_LIBS=""
101 PTHREAD_CFLAGS=""
102 fi
103 LIBS="$save_LIBS"
104 CFLAGS="$save_CFLAGS"
105 fi
107 # We must check for the threads library under a number of different
108 # names; the ordering is very important because some systems
109 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
110 # libraries is broken (non-POSIX).
112 # Create a list of thread flags to try. Items starting with a "-" are
113 # C compiler flags, and other items are library names, except for "none"
114 # which indicates that we try without any flags at all, and "pthread-config"
115 # which is a program returning the flags for the Pth emulation library.
117 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
119 # The ordering *is* (sometimes) important. Some notes on the
120 # individual items follow:
122 # pthreads: AIX (must check this before -lpthread)
123 # none: in case threads are in libc; should be tried before -Kthread and
124 # other compiler flags to prevent continual compiler warnings
125 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
126 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
127 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
128 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
129 # -pthreads: Solaris/gcc
130 # -mthreads: Mingw32/gcc, Lynx/gcc
131 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
132 # doesn't hurt to check since this sometimes defines pthreads too;
133 # also defines -D_REENTRANT)
134 # ... -mt is also the pthreads flag for HP/aCC
135 # pthread: Linux, etcetera
136 # --thread-safe: KAI C++
137 # pthread-config: use pthread-config program (for GNU Pth library)
139 case "${host_cpu}-${host_os}" in
140 *solaris*)
142 # On Solaris (at least, for some versions), libc contains stubbed
143 # (non-functional) versions of the pthreads routines, so link-based
144 # tests will erroneously succeed. (We need to link with -pthreads/-mt/
145 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather
146 # a function called by this macro, so we could check for that, but
147 # who knows whether they'll stub that too in a future libc.) So,
148 # we'll just look for -pthreads and -lpthread first:
150 acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
151 ;;
152 esac
154 if test x"$acx_pthread_ok" = xno; then
155 for flag in $acx_pthread_flags; do
157 case $flag in
158 none)
159 AC_MSG_CHECKING([whether pthreads work without any flags])
160 ;;
162 -*)
163 AC_MSG_CHECKING([whether pthreads work with $flag])
164 PTHREAD_CFLAGS="$flag"
165 ;;
167 pthread-config)
168 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
169 if test x"$acx_pthread_config" = xno; then continue; fi
170 PTHREAD_CFLAGS="`pthread-config --cflags`"
171 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
172 ;;
174 *)
175 AC_MSG_CHECKING([for the pthreads library -l$flag])
176 PTHREAD_LIBS="-l$flag"
177 ;;
178 esac
180 save_LIBS="$LIBS"
181 save_CFLAGS="$CFLAGS"
182 LIBS="$PTHREAD_LIBS $LIBS"
183 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
185 # Check for various functions. We must include pthread.h,
186 # since some functions may be macros. (On the Sequent, we
187 # need a special flag -Kthread to make this header compile.)
188 # We check for pthread_join because it is in -lpthread on IRIX
189 # while pthread_create is in libc. We check for pthread_attr_init
190 # due to DEC craziness with -lpthreads. We check for
191 # pthread_cleanup_push because it is one of the few pthread
192 # functions on Solaris that doesn't have a non-functional libc stub.
193 # We try pthread_create on general principles.
194 AC_TRY_LINK([#include <pthread.h>],
195 [pthread_t th; pthread_join(th, 0);
196 pthread_attr_init(0); pthread_cleanup_push(0, 0);
197 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
198 [acx_pthread_ok=yes])
200 LIBS="$save_LIBS"
201 CFLAGS="$save_CFLAGS"
203 AC_MSG_RESULT($acx_pthread_ok)
204 if test "x$acx_pthread_ok" = xyes; then
205 break;
206 fi
208 PTHREAD_LIBS=""
209 PTHREAD_CFLAGS=""
210 done
211 fi
213 # Various other checks:
214 if test "x$acx_pthread_ok" = xyes; then
215 save_LIBS="$LIBS"
216 LIBS="$PTHREAD_LIBS $LIBS"
217 save_CFLAGS="$CFLAGS"
218 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
220 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
221 AC_MSG_CHECKING([for joinable pthread attribute])
222 attr_name=unknown
223 for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
224 AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
225 [attr_name=$attr; break])
226 done
227 AC_MSG_RESULT($attr_name)
228 if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
229 AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
230 [Define to necessary symbol if this constant
231 uses a non-standard name on your system.])
232 fi
234 AC_MSG_CHECKING([if more special flags are required for pthreads])
235 flag=no
236 case "${host_cpu}-${host_os}" in
237 *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
238 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
239 esac
240 AC_MSG_RESULT(${flag})
241 if test "x$flag" != xno; then
242 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
243 fi
245 LIBS="$save_LIBS"
246 CFLAGS="$save_CFLAGS"
248 # More AIX lossage: must compile with xlc_r or cc_r
249 if test x"$GCC" != xyes; then
250 AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
251 else
252 PTHREAD_CC=$CC
253 fi
254 else
255 PTHREAD_CC="$CC"
256 fi
258 AC_SUBST(PTHREAD_LIBS)
259 AC_SUBST(PTHREAD_CFLAGS)
260 AC_SUBST(PTHREAD_CC)
262 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
263 if test x"$acx_pthread_ok" = xyes; then
264 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
265 :
266 else
267 acx_pthread_ok=no
268 $2
269 fi
270 AC_LANG_RESTORE
271 ])dnl ACX_PTHREAD