dnl Available from the GNU Autoconf Macro Archive at:

dnl http://www.gnu.org/software/ac-archive/htmldoc/acx_pthread.html

dnl

AC_DEFUN([ACX_PTHREAD], [

AC_REQUIRE([AC_CANONICAL_HOST])

AC_LANG_SAVE

AC_LANG_C

acx_pthread_ok=no

# We used to check for pthread.h first, but this fails if pthread.h

# requires special compiler flags (e.g. on True64 or Sequent).

# It gets checked for in the link test anyway.

# First of all, check if the user has set any of the PTHREAD_LIBS,

# etcetera environment variables, and if threads linking works using

# them:

if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then

save_CFLAGS="$CFLAGS"

CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

save_LIBS="$LIBS"

LIBS="$PTHREAD_LIBS $LIBS"

AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])

AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)

AC_MSG_RESULT($acx_pthread_ok)

if test x"$acx_pthread_ok" = xno; then

PTHREAD_LIBS=""

PTHREAD_CFLAGS=""

fi

LIBS="$save_LIBS"

CFLAGS="$save_CFLAGS"

fi

# We must check for the threads library under a number of different

# names; the ordering is very important because some systems

# (e.g. DEC) have both -lpthread and -lpthreads, where one of the

# libraries is broken (non-POSIX).

# Create a list of thread flags to try. Items starting with a "-" are

# C compiler flags, and other items are library names, except for "none"

# which indicates that we try without any flags at all, and "pthread-config"

# which is a program returning the flags for the Pth emulation library.

acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"

# The ordering *is* (sometimes) important. Some notes on the

# individual items follow:

# pthreads: AIX (must check this before -lpthread)

# none: in case threads are in libc; should be tried before -Kthread and

# other compiler flags to prevent continual compiler warnings

# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)

# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)

# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)

# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)

# -pthreads: Solaris/gcc

# -mthreads: Mingw32/gcc, Lynx/gcc

# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it

# doesn't hurt to check since this sometimes defines pthreads too;

# also defines -D_REENTRANT)

# pthread: Linux, etcetera

# --thread-safe: KAI C

# pthread-config: use pthread-config program (for GNU Pth library)

case "${host_cpu}-${host_os}" in

*solaris*)

# On Solaris (at least, for some versions), libc contains stubbed

# (non-functional) versions of the pthreads routines, so link-based

# tests will erroneously succeed. (We need to link with -pthread or

# -lpthread.) (The stubs are missing pthread_cleanup_push, or rather

# a function called by this macro, so we could check for that, but

# who knows whether they'll stub that too in a future libc.) So,

# we'll just look for -pthreads and -lpthread first:

acx_pthread_flags="-pthread -pthreads pthread -mt $acx_pthread_flags"

;;

esac

if test x"$acx_pthread_ok" = xno; then

for flag in $acx_pthread_flags; do

case $flag in

none)

AC_MSG_CHECKING([whether pthreads work without any flags])

;;

-*)

AC_MSG_CHECKING([whether pthreads work with $flag])

PTHREAD_CFLAGS="$flag"

;;

pthread-config)

AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)

if test x"$acx_pthread_config" = xno; then continue; fi

PTHREAD_CFLAGS="`pthread-config --cflags`"

PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"

;;

*)

AC_MSG_CHECKING([for the pthreads library -l$flag])

PTHREAD_LIBS="-l$flag"

;;

esac

save_LIBS="$LIBS"

save_CFLAGS="$CFLAGS"

LIBS="$PTHREAD_LIBS $LIBS"

CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

# Check for various functions. We must include pthread.h,

# since some functions may be macros. (On the Sequent, we

# need a special flag -Kthread to make this header compile.)

# We check for pthread_join because it is in -lpthread on IRIX

# while pthread_create is in libc. We check for pthread_attr_init

# due to DEC craziness with -lpthreads. We check for

# pthread_cleanup_push because it is one of the few pthread

# functions on Solaris that doesn't have a non-functional libc stub.

# We try pthread_create on general principles.

AC_TRY_LINK([#include <pthread.h>],

[pthread_t th; pthread_join(th, 0);

pthread_attr_init(0); pthread_cleanup_push(0, 0);

pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],

[acx_pthread_ok=yes])

LIBS="$save_LIBS"

CFLAGS="$save_CFLAGS"

AC_MSG_RESULT($acx_pthread_ok)

if test "x$acx_pthread_ok" = xyes; then

break;

fi

PTHREAD_LIBS=""

PTHREAD_CFLAGS=""

done

fi

# Various other checks:

if test "x$acx_pthread_ok" = xyes; then

save_LIBS="$LIBS"

LIBS="$PTHREAD_LIBS $LIBS"

save_CFLAGS="$CFLAGS"

CFLAGS="$CFLAGS $PTHREAD_CFLAGS"

# Detect AIX lossage: threads are created detached by default

# and the JOINABLE attribute has a nonstandard name (UNDETACHED).

AC_MSG_CHECKING([for joinable pthread attribute])

AC_TRY_LINK([#include <pthread.h>],

[int attr=PTHREAD_CREATE_JOINABLE;],

ok=PTHREAD_CREATE_JOINABLE, ok=unknown)

if test x"$ok" = xunknown; then

AC_TRY_LINK([#include <pthread.h>],

[int attr=PTHREAD_CREATE_UNDETACHED;],

ok=PTHREAD_CREATE_UNDETACHED, ok=unknown)

fi

if test x"$ok" != xPTHREAD_CREATE_JOINABLE; then

AC_DEFINE(PTHREAD_CREATE_JOINABLE, $ok,

[Define to the necessary symbol if this constant

uses a non-standard name on your system.])

fi

AC_MSG_RESULT(${ok})

if test x"$ok" = xunknown; then

AC_MSG_WARN([we do not know how to create joinable pthreads])

fi

AC_MSG_CHECKING([if more special flags are required for pthreads])

flag=no

case "${host_cpu}-${host_os}" in

*-aix* | *-freebsd*) flag="-D_THREAD_SAFE";;

*solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;

esac

AC_MSG_RESULT(${flag})

if test "x$flag" != xno; then

PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"

fi

LIBS="$save_LIBS"

CFLAGS="$save_CFLAGS"

# More AIX lossage: must compile with cc_r

AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC})

else

PTHREAD_CC="$CC"

fi

AC_SUBST(PTHREAD_LIBS)

AC_SUBST(PTHREAD_CFLAGS)

AC_SUBST(PTHREAD_CC)

# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:

if test x"$acx_pthread_ok" = xyes; then

ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])

:

else

acx_pthread_ok=no

$2

fi

AC_LANG_RESTORE

])dnl ACX_PTHREAD

AC_DEFUN(AC_CHECK_GLOBAL,

[

for ac_global in $1

do

ac_tr_global=HAVE_`echo $ac_global | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`

AC_MSG_CHECKING([for global variable ${ac_global}])

AC_CACHE_VAL(ac_cv_global_$ac_global,

[

AC_TRY_LINK(dnl

[/* no includes */],

[ extern long int $ac_global; exit((int)$ac_global)],

eval "ac_cv_global_${ac_global}=yes",

eval "ac_cv_global_${ac_global}=no"

)

]

)

if eval "test \"`echo '$ac_cv_global_'$ac_global`\" = yes"; then

AC_MSG_RESULT(yes)

AC_DEFINE_UNQUOTED($ac_tr_global,1,Define if the global variable $ac_global is available)

else

AC_MSG_RESULT(no)

fi

done

])