1 dnl Available from the GNU Autoconf Macro Archive at:
2 dnl http://www.gnu.org/software/ac-archive/htmldoc/acx_pthread.html
4 AC_DEFUN([ACX_PTHREAD], [
5 AC_REQUIRE([AC_CANONICAL_HOST])
10 # We used to check for pthread.h first, but this fails if pthread.h
11 # requires special compiler flags (e.g. on True64 or Sequent).
12 # It gets checked for in the link test anyway.
14 # First of all, check if the user has set any of the PTHREAD_LIBS,
15 # etcetera environment variables, and if threads linking works using
17 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
19 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
21 LIBS="$PTHREAD_LIBS $LIBS"
22 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
23 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
24 AC_MSG_RESULT($acx_pthread_ok)
25 if test x"$acx_pthread_ok" = xno; then
33 # We must check for the threads library under a number of different
34 # names; the ordering is very important because some systems
35 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
36 # libraries is broken (non-POSIX).
38 # Create a list of thread flags to try. Items starting with a "-" are
39 # C compiler flags, and other items are library names, except for "none"
40 # which indicates that we try without any flags at all.
42 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt"
44 # The ordering *is* (sometimes) important. Some notes on the
45 # individual items follow:
47 # pthreads: AIX (must check this before -lpthread)
48 # none: in case threads are in libc; should be tried before -Kthread and
49 # other compiler flags to prevent continual compiler warnings
50 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
51 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
52 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
53 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
54 # -pthreads: Solaris/gcc
55 # -mthreads: Mingw32/gcc, Lynx/gcc
56 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
57 # doesn't hurt to check since this sometimes defines pthreads too;
58 # also defines -D_REENTRANT)
59 # pthread: Linux, etcetera
60 # --thread-safe: KAI C++
62 case "${host_cpu}-${host_os}" in
65 # On Solaris (at least, for some versions), libc contains stubbed
66 # (non-functional) versions of the pthreads routines, so link-based
67 # tests will erroneously succeed. (We need to link with -pthread or
68 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather
69 # a function called by this macro, so we could check for that, but
70 # who knows whether they'll stub that too in a future libc.) So,
71 # we'll just look for -pthreads and -lpthread first:
73 acx_pthread_flags="-pthread -pthreads pthread -mt $acx_pthread_flags"
77 if test x"$acx_pthread_ok" = xno; then
78 for flag in $acx_pthread_flags; do
82 AC_MSG_CHECKING([whether pthreads work without any flags])
86 AC_MSG_CHECKING([whether pthreads work with $flag])
87 PTHREAD_CFLAGS="$flag"
91 AC_MSG_CHECKING([for the pthreads library -l$flag])
92 PTHREAD_LIBS="-l$flag"
98 LIBS="$PTHREAD_LIBS $LIBS"
99 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
101 # Check for various functions. We must include pthread.h,
102 # since some functions may be macros. (On the Sequent, we
103 # need a special flag -Kthread to make this header compile.)
104 # We check for pthread_join because it is in -lpthread on IRIX
105 # while pthread_create is in libc. We check for pthread_attr_init
106 # due to DEC craziness with -lpthreads. We check for
107 # pthread_cleanup_push because it is one of the few pthread
108 # functions on Solaris that doesn't have a non-functional libc stub.
109 # We try pthread_create on general principles.
110 AC_TRY_LINK([#include <pthread.h>],
111 [pthread_t th; pthread_join(th, 0);
112 pthread_attr_init(0); pthread_cleanup_push(0, 0);
113 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
114 [acx_pthread_ok=yes])
117 CFLAGS="$save_CFLAGS"
119 AC_MSG_RESULT($acx_pthread_ok)
120 if test "x$acx_pthread_ok" = xyes; then
129 # Various other checks:
130 if test "x$acx_pthread_ok" = xyes; then
132 LIBS="$PTHREAD_LIBS $LIBS"
133 save_CFLAGS="$CFLAGS"
134 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
136 # Detect AIX lossage: threads are created detached by default
137 # and the JOINABLE attribute has a nonstandard name (UNDETACHED).
138 AC_MSG_CHECKING([for joinable pthread attribute])
139 AC_TRY_LINK([#include <pthread.h>],
140 [int attr=PTHREAD_CREATE_JOINABLE;],
141 ok=PTHREAD_CREATE_JOINABLE, ok=unknown)
142 if test x"$ok" = xunknown; then
143 AC_TRY_LINK([#include <pthread.h>],
144 [int attr=PTHREAD_CREATE_UNDETACHED;],
145 ok=PTHREAD_CREATE_UNDETACHED, ok=unknown)
147 if test x"$ok" != xPTHREAD_CREATE_JOINABLE; then
148 AC_DEFINE(PTHREAD_CREATE_JOINABLE, $ok,
149 [Define to the necessary symbol if this constant
150 uses a non-standard name on your system.])
153 if test x"$ok" = xunknown; then
154 AC_MSG_WARN([we do not know how to create joinable pthreads])
157 AC_MSG_CHECKING([if more special flags are required for pthreads])
159 case "${host_cpu}-${host_os}" in
160 *-aix* | *-freebsd*) flag="-D_THREAD_SAFE";;
161 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
163 AC_MSG_RESULT(${flag})
164 if test "x$flag" != xno; then
165 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
169 CFLAGS="$save_CFLAGS"
171 # More AIX lossage: must compile with cc_r
172 AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC})
177 AC_SUBST(PTHREAD_LIBS)
178 AC_SUBST(PTHREAD_CFLAGS)
181 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
182 if test x"$acx_pthread_ok" = xyes; then
183 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])