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dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) |
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dnl |
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dnl This macro figures out how to build C programs using POSIX |
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dnl threads. It sets the PTHREAD_LIBS output variable to the threads |
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dnl library and linker flags, and the PTHREAD_CFLAGS output variable |
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dnl to any special C compiler flags that are needed. (The user can also |
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dnl force certain compiler flags/libs to be tested by setting these |
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dnl environment variables.) |
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dnl |
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dnl Also sets PTHREAD_CC to any special C compiler that is needed for |
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dnl multi-threaded programs (defaults to the value of CC otherwise). |
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dnl (This is necessary on AIX to use the special cc_r compiler alias.) |
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dnl |
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dnl If you are only building threads programs, you may wish to |
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dnl use these variables in your default LIBS, CFLAGS, and CC: |
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dnl |
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dnl LIBS="$PTHREAD_LIBS $LIBS" |
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dnl CFLAGS="$CFLAGS $PTHREAD_CFLAGS" |
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dnl CC="$PTHREAD_CC" |
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dnl |
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dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute |
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dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE |
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dnl to that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). |
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dnl |
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dnl ACTION-IF-FOUND is a list of shell commands to run if a threads |
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dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands |
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dnl to run it if it is not found. If ACTION-IF-FOUND is not specified, |
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dnl the default action will define HAVE_PTHREAD. |
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dnl |
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dnl Please let the authors know if this macro fails on any platform, |
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dnl or if you have any other suggestions or comments. This macro was |
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dnl based on work by SGJ on autoconf scripts for FFTW (www.fftw.org) |
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dnl (with help from M. Frigo), as well as ac_pthread and hb_pthread |
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dnl macros posted by AFC to the autoconf macro repository. We are also |
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dnl grateful for the helpful feedback of numerous users. |
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dnl |
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dnl @version $Id$ |
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dnl @author Steven G. Johnson <stevenj@alum.mit.edu> and Alejandro Forero Cuervo <bachue@bachue.com> |
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AC_DEFUN([ACX_PTHREAD], [ |
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AC_REQUIRE([AC_CANONICAL_HOST]) |
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AC_LANG_SAVE |
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AC_LANG_C |
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acx_pthread_ok=no |
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# We used to check for pthread.h first, but this fails if pthread.h |
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# requires special compiler flags (e.g. on True64 or Sequent). |
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# It gets checked for in the link test anyway. |
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|
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# First of all, check if the user has set any of the PTHREAD_LIBS, |
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# etcetera environment variables, and if threads linking works using |
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# them: |
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if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then |
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save_CFLAGS="$CFLAGS" |
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CFLAGS="$CFLAGS $PTHREAD_CFLAGS" |
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save_LIBS="$LIBS" |
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LIBS="$PTHREAD_LIBS $LIBS" |
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AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS]) |
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AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes) |
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AC_MSG_RESULT($acx_pthread_ok) |
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if test x"$acx_pthread_ok" = xno; then |
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PTHREAD_LIBS="" |
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PTHREAD_CFLAGS="" |
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fi |
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LIBS="$save_LIBS" |
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CFLAGS="$save_CFLAGS" |
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fi |
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# We must check for the threads library under a number of different |
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# names; the ordering is very important because some systems |
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# (e.g. DEC) have both -lpthread and -lpthreads, where one of the |
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# libraries is broken (non-POSIX). |
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# Create a list of thread flags to try. Items starting with a "-" are |
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# C compiler flags, and other items are library names, except for "none" |
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# which indicates that we try without any flags at all. |
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acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt" |
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# The ordering *is* (sometimes) important. Some notes on the |
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# individual items follow: |
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# pthreads: AIX (must check this before -lpthread) |
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# none: in case threads are in libc; should be tried before -Kthread and |
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# other compiler flags to prevent continual compiler warnings |
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# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) |
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# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) |
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# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) |
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# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads) |
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# -pthreads: Solaris/gcc |
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# -mthreads: Mingw32/gcc, Lynx/gcc |
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# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it |
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# doesn't hurt to check since this sometimes defines pthreads too; |
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# also defines -D_REENTRANT) |
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# pthread: Linux, etcetera |
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# --thread-safe: KAI C++ |
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case "${host_cpu}-${host_os}" in |
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*solaris*) |
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# On Solaris (at least, for some versions), libc contains stubbed |
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# (non-functional) versions of the pthreads routines, so link-based |
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# tests will erroneously succeed. (We need to link with -pthread or |
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# -lpthread.) (The stubs are missing pthread_cleanup_push, or rather |
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# a function called by this macro, so we could check for that, but |
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# who knows whether they'll stub that too in a future libc.) So, |
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# we'll just look for -pthreads and -lpthread first: |
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acx_pthread_flags="-pthread -pthreads pthread -mt $acx_pthread_flags" |
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;; |
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esac |
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if test x"$acx_pthread_ok" = xno; then |
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for flag in $acx_pthread_flags; do |
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case $flag in |
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none) |
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AC_MSG_CHECKING([whether pthreads work without any flags]) |
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;; |
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-*) |
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AC_MSG_CHECKING([whether pthreads work with $flag]) |
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PTHREAD_CFLAGS="$flag" |
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;; |
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*) |
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AC_MSG_CHECKING([for the pthreads library -l$flag]) |
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PTHREAD_LIBS="-l$flag" |
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;; |
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esac |
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save_LIBS="$LIBS" |
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save_CFLAGS="$CFLAGS" |
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LIBS="$PTHREAD_LIBS $LIBS" |
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CFLAGS="$CFLAGS $PTHREAD_CFLAGS" |
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# Check for various functions. We must include pthread.h, |
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# since some functions may be macros. (On the Sequent, we |
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# need a special flag -Kthread to make this header compile.) |
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# We check for pthread_join because it is in -lpthread on IRIX |
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# while pthread_create is in libc. We check for pthread_attr_init |
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# due to DEC craziness with -lpthreads. We check for |
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# pthread_cleanup_push because it is one of the few pthread |
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# functions on Solaris that doesn't have a non-functional libc stub. |
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# We try pthread_create on general principles. |
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AC_TRY_LINK([#include <pthread.h>], |
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[pthread_t th; pthread_join(th, 0); |
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pthread_attr_init(0); pthread_cleanup_push(0, 0); |
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pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], |
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[acx_pthread_ok=yes]) |
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LIBS="$save_LIBS" |
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CFLAGS="$save_CFLAGS" |
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AC_MSG_RESULT($acx_pthread_ok) |
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if test "x$acx_pthread_ok" = xyes; then |
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break; |
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fi |
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PTHREAD_LIBS="" |
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PTHREAD_CFLAGS="" |
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done |
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fi |
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# Various other checks: |
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if test "x$acx_pthread_ok" = xyes; then |
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save_LIBS="$LIBS" |
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LIBS="$PTHREAD_LIBS $LIBS" |
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save_CFLAGS="$CFLAGS" |
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CFLAGS="$CFLAGS $PTHREAD_CFLAGS" |
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# Detect AIX lossage: threads are created detached by default |
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# and the JOINABLE attribute has a nonstandard name (UNDETACHED). |
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AC_MSG_CHECKING([for joinable pthread attribute]) |
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AC_TRY_LINK([#include <pthread.h>], |
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[int attr=PTHREAD_CREATE_JOINABLE;], |
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ok=PTHREAD_CREATE_JOINABLE, ok=unknown) |
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if test x"$ok" = xunknown; then |
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AC_TRY_LINK([#include <pthread.h>], |
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[int attr=PTHREAD_CREATE_UNDETACHED;], |
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ok=PTHREAD_CREATE_UNDETACHED, ok=unknown) |
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fi |
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if test x"$ok" != xPTHREAD_CREATE_JOINABLE; then |
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AC_DEFINE(PTHREAD_CREATE_JOINABLE, $ok, |
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[Define to the necessary symbol if this constant |
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uses a non-standard name on your system.]) |
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fi |
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AC_MSG_RESULT(${ok}) |
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if test x"$ok" = xunknown; then |
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AC_MSG_WARN([we do not know how to create joinable pthreads]) |
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fi |
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AC_MSG_CHECKING([if more special flags are required for pthreads]) |
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flag=no |
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case "${host_cpu}-${host_os}" in |
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*-aix* | *-freebsd*) flag="-D_THREAD_SAFE";; |
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*solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";; |
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esac |
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AC_MSG_RESULT(${flag}) |
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if test "x$flag" != xno; then |
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PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS" |
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fi |
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LIBS="$save_LIBS" |
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CFLAGS="$save_CFLAGS" |
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# More AIX lossage: must compile with cc_r |
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AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC}) |
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else |
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PTHREAD_CC="$CC" |
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fi |
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AC_SUBST(PTHREAD_LIBS) |
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AC_SUBST(PTHREAD_CFLAGS) |
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AC_SUBST(PTHREAD_CC) |
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# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: |
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if test x"$acx_pthread_ok" = xyes; then |
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ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1]) |
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: |
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else |
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acx_pthread_ok=no |
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$2 |
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fi |
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AC_LANG_RESTORE |
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])dnl ACX_PTHREAD |