Blame m4/ax_pthread.m4

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# ===========================================================================
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#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
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# ===========================================================================
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#
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# SYNOPSIS
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#
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#   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
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#
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# DESCRIPTION
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#
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#   This macro figures out how to build C programs using POSIX threads. It
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#   sets the PTHREAD_LIBS output variable to the threads library and linker
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#   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
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#   flags that are needed. (The user can also force certain compiler
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#   flags/libs to be tested by setting these environment variables.)
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#
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#   Also sets PTHREAD_CC to any special C compiler that is needed for
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#   multi-threaded programs (defaults to the value of CC otherwise). (This
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#   is necessary on AIX to use the special cc_r compiler alias.)
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#
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#   NOTE: You are assumed to not only compile your program with these flags,
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#   but also link it with them as well. e.g. you should link with
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#   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
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#
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#   If you are only building threads programs, you may wish to use these
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#   variables in your default LIBS, CFLAGS, and CC:
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#
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#     LIBS="$PTHREAD_LIBS $LIBS"
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#     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
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#     CC="$PTHREAD_CC"
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#
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#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
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#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
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#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
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#
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#   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
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#   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
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#   PTHREAD_CFLAGS.
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#
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#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
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#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
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#   is not found. If ACTION-IF-FOUND is not specified, the default action
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#   will define HAVE_PTHREAD.
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#
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#   Please let the authors know if this macro fails on any platform, or if
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#   you have any other suggestions or comments. This macro was based on work
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#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
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#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
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#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
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#   grateful for the helpful feedback of numerous users.
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#
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#   Updated for Autoconf 2.68 by Daniel Richard G.
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#
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# LICENSE
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#
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#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
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#   Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG>
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#
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#   This program is free software: you can redistribute it and/or modify it
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#   under the terms of the GNU General Public License as published by the
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#   Free Software Foundation, either version 3 of the License, or (at your
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#   option) any later version.
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#
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#   This program is distributed in the hope that it will be useful, but
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#   WITHOUT ANY WARRANTY; without even the implied warranty of
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#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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#   Public License for more details.
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#
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#   You should have received a copy of the GNU General Public License along
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#   with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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#   As a special exception, the respective Autoconf Macro's copyright owner
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#   gives unlimited permission to copy, distribute and modify the configure
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#   scripts that are the output of Autoconf when processing the Macro. You
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#   need not follow the terms of the GNU General Public License when using
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#   or distributing such scripts, even though portions of the text of the
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#   Macro appear in them. The GNU General Public License (GPL) does govern
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#   all other use of the material that constitutes the Autoconf Macro.
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#
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#   This special exception to the GPL applies to versions of the Autoconf
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#   Macro released by the Autoconf Archive. When you make and distribute a
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#   modified version of the Autoconf Macro, you may extend this special
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#   exception to the GPL to apply to your modified version as well.
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#serial 21
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AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
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AC_DEFUN([AX_PTHREAD], [
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AC_REQUIRE([AC_CANONICAL_HOST])
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AC_LANG_PUSH([C])
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ax_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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# 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=$PTHREAD_CFLAGS])
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        AC_TRY_LINK_FUNC([pthread_join], [ax_pthread_ok=yes])
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        AC_MSG_RESULT([$ax_pthread_ok])
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        if test x"$ax_pthread_ok" = xno; then
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                PTHREAD_LIBS=""
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                PTHREAD_CFLAGS=""
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        fi
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        LIBS="$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, and "pthread-config"
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# which is a program returning the flags for the Pth emulation library.
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ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
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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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#      ... -mt is also the pthreads flag for HP/aCC
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# pthread: Linux, etcetera
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# --thread-safe: KAI C++
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# pthread-config: use pthread-config program (for GNU Pth library)
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case ${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 -pthreads/-mt/
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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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        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
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        ;;
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        darwin*)
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        ax_pthread_flags="-pthread $ax_pthread_flags"
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        ;;
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esac
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# Clang doesn't consider unrecognized options an error unless we specify
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# -Werror. We throw in some extra Clang-specific options to ensure that
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# this doesn't happen for GCC, which also accepts -Werror.
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AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
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save_CFLAGS="$CFLAGS"
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ax_pthread_extra_flags="-Werror"
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CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
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AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
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                  [AC_MSG_RESULT([yes])],
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                  [ax_pthread_extra_flags=
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                   AC_MSG_RESULT([no])])
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CFLAGS="$save_CFLAGS"
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if test x"$ax_pthread_ok" = xno; then
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for flag in $ax_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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                pthread-config)
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                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
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                if test x"$ax_pthread_config" = xno; then continue; fi
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                PTHREAD_CFLAGS="`pthread-config --cflags`"
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                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
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                ;;
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                *)
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                AC_MSG_CHECKING([for the pthreads library -l$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 $ax_pthread_extra_flags"
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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_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
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                        static void routine(void *a) { a = 0; }
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                        static void *start_routine(void *a) { return a; }],
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                       [pthread_t th; pthread_attr_t attr;
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                        pthread_create(&th, 0, start_routine, 0);
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                        pthread_join(th, 0);
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                        pthread_attr_init(&attr);
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                        pthread_cleanup_push(routine, 0);
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                        pthread_cleanup_pop(0) /* ; */])],
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                [ax_pthread_ok=yes],
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                [])
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        LIBS="$save_LIBS"
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        CFLAGS="$save_CFLAGS"
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        AC_MSG_RESULT([$ax_pthread_ok])
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        if test "x$ax_pthread_ok" = xyes; then
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                break;
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        fi
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        PTHREAD_LIBS=""
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        PTHREAD_CFLAGS=""
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done
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fi
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# Various other checks:
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if test "x$ax_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: JOINABLE attribute is called UNDETACHED.
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        AC_MSG_CHECKING([for joinable pthread attribute])
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        attr_name=unknown
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        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
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            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
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                           [int attr = $attr; return attr /* ; */])],
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                [attr_name=$attr; break],
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                [])
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        done
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        AC_MSG_RESULT([$attr_name])
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        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
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            AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
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                               [Define to 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_CHECKING([if more special flags are required for pthreads])
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        flag=no
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        case ${host_os} in
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            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
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            osf* | hpux*) flag="-D_REENTRANT";;
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            solaris*)
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            if test "$GCC" = "yes"; then
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                flag="-D_REENTRANT"
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            else
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                # TODO: What about Clang on Solaris?
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                flag="-mt -D_REENTRANT"
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            fi
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            ;;
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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 $PTHREAD_CFLAGS"
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        fi
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        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
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            [ax_cv_PTHREAD_PRIO_INHERIT], [
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                AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
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                                                [[int i = PTHREAD_PRIO_INHERIT;]])],
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                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
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                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
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            ])
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        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
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            [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
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        LIBS="$save_LIBS"
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        CFLAGS="$save_CFLAGS"
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        # More AIX lossage: compile with *_r variant
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        if test "x$GCC" != xyes; then
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            case $host_os in
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                aix*)
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                AS_CASE(["x/$CC"],
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                  [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
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                  [#handle absolute path differently from PATH based program lookup
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                   AS_CASE(["x$CC"],
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                     [x/*],
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                     [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
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                     [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
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                ;;
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            esac
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        fi
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fi
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test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
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AC_SUBST([PTHREAD_LIBS])
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AC_SUBST([PTHREAD_CFLAGS])
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AC_SUBST([PTHREAD_CC])
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# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
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if test x"$ax_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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        ax_pthread_ok=no
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        $2
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fi
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AC_LANG_POP
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])dnl AX_PTHREAD