1dnl Available from the GNU Autoconf Macro Archive at:
2dnl http://www.gnu.org/software/ac-archive/htmldoc/acx_pthread.html
3dnl
4AC_DEFUN([ACX_PTHREAD], [
5AC_REQUIRE([AC_CANONICAL_HOST])
6AC_LANG_SAVE
7AC_LANG_C
8acx_pthread_ok=no
9
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.
13
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
16# them:
17if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
18        save_CFLAGS="$CFLAGS"
19        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
20        save_LIBS="$LIBS"
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"$acx_pthread_ok" = xno; then
26                PTHREAD_LIBS=""
27                PTHREAD_CFLAGS=""
28        fi
29        LIBS="$save_LIBS"
30        CFLAGS="$save_CFLAGS"
31fi
32
33# We must check for the threads library under a number of different
34# names; the ordering is very important because some systems
35# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
36# libraries is broken (non-POSIX).
37
38# Create a list of thread flags to try.  Items starting with a "-" are
39# C compiler flags, and other items are library names, except for "none"
40# which indicates that we try without any flags at all, and "pthread-config"
41# which is a program returning the flags for the Pth emulation library.
42
43acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
44
45# The ordering *is* (sometimes) important.  Some notes on the
46# individual items follow:
47
48# pthreads: AIX (must check this before -lpthread)
49# none: in case threads are in libc; should be tried before -Kthread and
50#       other compiler flags to prevent continual compiler warnings
51# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
52# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
53# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
54# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
55# -pthreads: Solaris/gcc
56# -mthreads: Mingw32/gcc, Lynx/gcc
57# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
58#      doesn't hurt to check since this sometimes defines pthreads too;
59#      also defines -D_REENTRANT)
60# pthread: Linux, etcetera
61# --thread-safe: KAI C++
62# pthread-config: use pthread-config program (for GNU Pth library)
63
64case "${host_cpu}-${host_os}" in
65        *solaris*)
66
67        # On Solaris (at least, for some versions), libc contains stubbed
68        # (non-functional) versions of the pthreads routines, so link-based
69        # tests will erroneously succeed.  (We need to link with -pthread or
70        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
71        # a function called by this macro, so we could check for that, but
72        # who knows whether they'll stub that too in a future libc.)  So,
73        # we'll just look for -pthreads and -lpthread first:
74
75        acx_pthread_flags="-pthread -pthreads pthread -mt $acx_pthread_flags"
76        ;;
77esac
78
79if test x"$acx_pthread_ok" = xno; then
80for flag in $acx_pthread_flags; do
81
82        case $flag in
83                none)
84                AC_MSG_CHECKING([whether pthreads work without any flags])
85                ;;
86
87                -*)
88                AC_MSG_CHECKING([whether pthreads work with $flag])
89                PTHREAD_CFLAGS="$flag"
90                ;;
91
92		pthread-config)
93		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
94		if test x"$acx_pthread_config" = xno; then continue; fi
95		PTHREAD_CFLAGS="`pthread-config --cflags`"
96		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
97		;;
98
99                *)
100                AC_MSG_CHECKING([for the pthreads library -l$flag])
101                PTHREAD_LIBS="-l$flag"
102                ;;
103        esac
104
105        save_LIBS="$LIBS"
106        save_CFLAGS="$CFLAGS"
107        LIBS="$PTHREAD_LIBS $LIBS"
108        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
109
110        # Check for various functions.  We must include pthread.h,
111        # since some functions may be macros.  (On the Sequent, we
112        # need a special flag -Kthread to make this header compile.)
113        # We check for pthread_join because it is in -lpthread on IRIX
114        # while pthread_create is in libc.  We check for pthread_attr_init
115        # due to DEC craziness with -lpthreads.  We check for
116        # pthread_cleanup_push because it is one of the few pthread
117        # functions on Solaris that doesn't have a non-functional libc stub.
118        # We try pthread_create on general principles.
119        AC_TRY_LINK([#include <pthread.h>],
120                    [pthread_t th; pthread_join(th, 0);
121                     pthread_attr_init(0); pthread_cleanup_push(0, 0);
122                     pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
123                    [acx_pthread_ok=yes])
124
125        LIBS="$save_LIBS"
126        CFLAGS="$save_CFLAGS"
127
128        AC_MSG_RESULT($acx_pthread_ok)
129        if test "x$acx_pthread_ok" = xyes; then
130                break;
131        fi
132
133        PTHREAD_LIBS=""
134        PTHREAD_CFLAGS=""
135done
136fi
137
138# Various other checks:
139if test "x$acx_pthread_ok" = xyes; then
140        save_LIBS="$LIBS"
141        LIBS="$PTHREAD_LIBS $LIBS"
142        save_CFLAGS="$CFLAGS"
143        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
144
145        # Detect AIX lossage: threads are created detached by default
146        # and the JOINABLE attribute has a nonstandard name (UNDETACHED).
147        AC_MSG_CHECKING([for joinable pthread attribute])
148        AC_TRY_LINK([#include <pthread.h>],
149                    [int attr=PTHREAD_CREATE_JOINABLE;],
150                    ok=PTHREAD_CREATE_JOINABLE, ok=unknown)
151        if test x"$ok" = xunknown; then
152                AC_TRY_LINK([#include <pthread.h>],
153                            [int attr=PTHREAD_CREATE_UNDETACHED;],
154                            ok=PTHREAD_CREATE_UNDETACHED, ok=unknown)
155        fi
156        if test x"$ok" != xPTHREAD_CREATE_JOINABLE; then
157                AC_DEFINE(PTHREAD_CREATE_JOINABLE, $ok,
158                          [Define to the necessary symbol if this constant
159                           uses a non-standard name on your system.])
160        fi
161        AC_MSG_RESULT(${ok})
162        if test x"$ok" = xunknown; then
163                AC_MSG_WARN([we do not know how to create joinable pthreads])
164        fi
165
166        AC_MSG_CHECKING([if more special flags are required for pthreads])
167        flag=no
168        case "${host_cpu}-${host_os}" in
169                *-aix* | *-freebsd*)     flag="-D_THREAD_SAFE";;
170                *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
171        esac
172        AC_MSG_RESULT(${flag})
173        if test "x$flag" != xno; then
174                PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
175        fi
176
177        LIBS="$save_LIBS"
178        CFLAGS="$save_CFLAGS"
179
180        # More AIX lossage: must compile with cc_r
181        AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC})
182else
183        PTHREAD_CC="$CC"
184fi
185
186AC_SUBST(PTHREAD_LIBS)
187AC_SUBST(PTHREAD_CFLAGS)
188AC_SUBST(PTHREAD_CC)
189
190# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
191if test x"$acx_pthread_ok" = xyes; then
192        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
193        :
194else
195        acx_pthread_ok=no
196        $2
197fi
198AC_LANG_RESTORE
199])dnl ACX_PTHREAD
200
201
202AC_DEFUN(AC_CHECK_GLOBAL,
203[
204for ac_global in $1
205do
206   ac_tr_global=HAVE_`echo $ac_global | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`
207   AC_MSG_CHECKING([for global variable ${ac_global}])
208   AC_CACHE_VAL(ac_cv_global_$ac_global,
209   [
210    AC_TRY_LINK(dnl
211    [/* no includes */],
212    [ extern long int $ac_global;  exit((int)$ac_global)],
213    eval "ac_cv_global_${ac_global}=yes",
214    eval "ac_cv_global_${ac_global}=no"
215    )
216   ]
217   )
218  if eval "test \"`echo '$ac_cv_global_'$ac_global`\" = yes"; then
219    AC_MSG_RESULT(yes)
220    AC_DEFINE_UNQUOTED($ac_tr_global,1,Define if the global variable $ac_global is available)
221  else
222    AC_MSG_RESULT(no)
223  fi
224done
225])
226
227
228
229