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[m6w6/libmemcached] / m4 / acx_pthread.m4
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
87 AC_DEFUN([ACX_PTHREAD], [
88 AC_REQUIRE([AC_CANONICAL_HOST])
89 AC_LANG_PUSH([C])
90 acx_pthread_ok=no
91
92 # We used to check for pthread.h first, but this fails if pthread.h
93 # requires special compiler flags (e.g. on True64 or Sequent).
94 # It gets checked for in the link test anyway.
95
96 # First of all, check if the user has set any of the PTHREAD_LIBS,
97 # etcetera environment variables, and if threads linking works using
98 # them:
99 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
100 save_CFLAGS="$CFLAGS"
101 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
102 save_LIBS="$LIBS"
103 LIBS="$PTHREAD_LIBS $LIBS"
104 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
105 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
106 AC_MSG_RESULT($acx_pthread_ok)
107 if test x"$acx_pthread_ok" = xno; then
108 PTHREAD_LIBS=""
109 PTHREAD_CFLAGS=""
110 fi
111 LIBS="$save_LIBS"
112 CFLAGS="$save_CFLAGS"
113 fi
114
115 # We must check for the threads library under a number of different
116 # names; the ordering is very important because some systems
117 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
118 # libraries is broken (non-POSIX).
119
120 # Create a list of thread flags to try. Items starting with a "-" are
121 # C compiler flags, and other items are library names, except for "none"
122 # which indicates that we try without any flags at all, and "pthread-config"
123 # which is a program returning the flags for the Pth emulation library.
124
125 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
126
127 # The ordering *is* (sometimes) important. Some notes on the
128 # individual items follow:
129
130 # pthreads: AIX (must check this before -lpthread)
131 # none: in case threads are in libc; should be tried before -Kthread and
132 # other compiler flags to prevent continual compiler warnings
133 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
134 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
135 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
136 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
137 # -pthreads: Solaris/gcc
138 # -mthreads: Mingw32/gcc, Lynx/gcc
139 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
140 # doesn't hurt to check since this sometimes defines pthreads too;
141 # also defines -D_REENTRANT)
142 # ... -mt is also the pthreads flag for HP/aCC
143 # pthread: Linux, etcetera
144 # --thread-safe: KAI C++
145 # pthread-config: use pthread-config program (for GNU Pth library)
146
147 case "${host_cpu}-${host_os}" in
148 *solaris*)
149
150 # On Solaris (at least, for some versions), libc contains stubbed
151 # (non-functional) versions of the pthreads routines, so link-based
152 # tests will erroneously succeed. (We need to link with -pthreads/-mt/
153 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather
154 # a function called by this macro, so we could check for that, but
155 # who knows whether they'll stub that too in a future libc.) So,
156 # we'll just look for -pthreads and -lpthread first:
157
158 acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
159 ;;
160 esac
161
162 if test x"$acx_pthread_ok" = xno; then
163 for flag in $acx_pthread_flags; do
164
165 case $flag in
166 none)
167 AC_MSG_CHECKING([whether pthreads work without any flags])
168 ;;
169
170 -*)
171 AC_MSG_CHECKING([whether pthreads work with $flag])
172 PTHREAD_CFLAGS="$flag"
173 ;;
174
175 pthread-config)
176 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
177 if test x"$acx_pthread_config" = xno; then continue; fi
178 PTHREAD_CFLAGS="`pthread-config --cflags`"
179 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
180 ;;
181
182 *)
183 AC_MSG_CHECKING([for the pthreads library -l$flag])
184 PTHREAD_LIBS="-l$flag"
185 ;;
186 esac
187
188 save_LIBS="$LIBS"
189 save_CFLAGS="$CFLAGS"
190 LIBS="$PTHREAD_LIBS $LIBS"
191 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
192
193 # Check for various functions. We must include pthread.h,
194 # since some functions may be macros. (On the Sequent, we
195 # need a special flag -Kthread to make this header compile.)
196 # We check for pthread_join because it is in -lpthread on IRIX
197 # while pthread_create is in libc. We check for pthread_attr_init
198 # due to DEC craziness with -lpthreads. We check for
199 # pthread_cleanup_push because it is one of the few pthread
200 # functions on Solaris that doesn't have a non-functional libc stub.
201 # We try pthread_create on general principles.
202 AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], [[pthread_t th; pthread_join(th, 0);
203 pthread_attr_init(0); pthread_cleanup_push(0, 0);
204 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ]])],[acx_pthread_ok=yes],[])
205
206 LIBS="$save_LIBS"
207 CFLAGS="$save_CFLAGS"
208
209 AC_MSG_RESULT($acx_pthread_ok)
210 if test "x$acx_pthread_ok" = xyes; then
211 break;
212 fi
213
214 PTHREAD_LIBS=""
215 PTHREAD_CFLAGS=""
216 done
217 fi
218
219 # Various other checks:
220 if test "x$acx_pthread_ok" = xyes; then
221 save_LIBS="$LIBS"
222 LIBS="$PTHREAD_LIBS $LIBS"
223 save_CFLAGS="$CFLAGS"
224 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
225
226 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
227 AC_MSG_CHECKING([for joinable pthread attribute])
228 attr_name=unknown
229 for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
230 AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], [[int attr=$attr; return attr;]])],[attr_name=$attr; break],[])
231 done
232 AC_MSG_RESULT($attr_name)
233 if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
234 AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
235 [Define to necessary symbol if this constant
236 uses a non-standard name on your system.])
237 fi
238
239 AC_MSG_CHECKING([if more special flags are required for pthreads])
240 flag=no
241 case "${host_cpu}-${host_os}" in
242 *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
243 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
244 esac
245 AC_MSG_RESULT(${flag})
246 if test "x$flag" != xno; then
247 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
248 fi
249
250 LIBS="$save_LIBS"
251 CFLAGS="$save_CFLAGS"
252
253 # More AIX lossage: must compile with xlc_r or cc_r
254 if test x"$GCC" != xyes; then
255 AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
256 else
257 PTHREAD_CC=$CC
258 fi
259 else
260 PTHREAD_CC="$CC"
261 fi
262
263 AC_SUBST(PTHREAD_LIBS)
264 AC_SUBST(PTHREAD_CFLAGS)
265 AC_SUBST(PTHREAD_CC)
266
267 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
268 if test x"$acx_pthread_ok" = xyes; then
269 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
270 :
271 else
272 acx_pthread_ok=no
273 $2
274 fi
275 AC_LANG_POP([])
276 ])dnl ACX_PTHREAD