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|
dnl
dnl NOTE: This file was modified. See the comments starting with 'CS:'
dnl for more information. In particular, it was changed to use C++
dnl instead of C.
dnl
dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
dnl
dnl @summary figure out how to build C++ programs using POSIX threads
dnl
dnl This macro figures out how to build C++ programs using POSIX threads.
dnl It sets the PTHREAD_LIBS output variable to the threads library and
dnl linker flags, and the PTHREAD_CXXFLAGS output variable to any special
dnl C++ compiler flags that are needed. (The user can also force certain
dnl compiler flags/libs to be tested by setting these environment
dnl variables.)
dnl
dnl Also sets PTHREAD_CXX to any special C++ compiler that is needed for
dnl multi-threaded programs (defaults to the value of CXX otherwise).
dnl (This is necessary on AIX to use the special xlC_r compiler alias.)
dnl
dnl NOTE: You are assumed to not only compile your program with these
dnl flags, but also link it with them as well. e.g. you should link
dnl with $PTHREAD_CXX $CXXFLAGS $PTHREAD_CXXFLAGS $LDFLAGS ... $PTHREAD_LIBS
dnl $LIBS
dnl
dnl If you are only building threads programs, you may wish to use
dnl these variables in your default LIBS, CXXFLAGS, and CXX:
dnl
dnl LIBS="$PTHREAD_LIBS $LIBS"
dnl CXXFLAGS="$CXXFLAGS $PTHREAD_CXXFLAGS"
dnl CXX="$PTHREAD_CXX"
dnl
dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
dnl
dnl ACTION-IF-FOUND is a list of shell commands to run if a threads
dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to
dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the
dnl default action will define HAVE_PTHREAD.
dnl
dnl Please let the authors know if this macro fails on any platform, or
dnl if you have any other suggestions or comments. This macro was based
dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with
dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros
dnl posted by Alejandro Forero Cuervo to the autoconf macro repository.
dnl We are also grateful for the helpful feedback of numerous users.
dnl
dnl @category InstalledPackages
dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
dnl @version 2006-05-29
dnl @license GPLWithACException
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_CXXFLAGS" != x; then
save_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $PTHREAD_CXXFLAGS"
save_LIBS="$LIBS"
LIBS="$PTHREAD_LIBS $LIBS"
AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CXXFLAGS=$PTHREAD_CXXFLAGS])
AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
AC_MSG_RESULT($acx_pthread_ok)
if test x"$acx_pthread_ok" = xno; then
PTHREAD_LIBS=""
PTHREAD_CXXFLAGS=""
fi
LIBS="$save_LIBS"
CXXFLAGS="$save_CXXFLAGS"
fi
# We must check for the threads library under a number of different
# names; the ordering is very important because some systems
# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
# libraries is broken (non-POSIX).
# Create a list of thread flags to try. Items starting with a "-" are
# C compiler flags, and other items are library names, except for "none"
# which indicates that we try without any flags at all, and "pthread-config"
# which is a program returning the flags for the Pth emulation library.
# CS: On GNU/Linux with gcc both -pthread and -lpthread are valid.
# However, libtool links libraries with -nostdlib which results in
# -pthread being stripped from the linker command line. To resolve
# this we move pthread from after -mthreads to after pthreads.
#
acx_pthread_flags="pthreads pthread none -Kthread -kthread lthread -pthread -pthreads -mthreads --thread-safe -mt pthread-config"
# The ordering *is* (sometimes) important. Some notes on the
# individual items follow:
# pthreads: AIX (must check this before -lpthread)
# none: in case threads are in libc; should be tried before -Kthread and
# other compiler flags to prevent continual compiler warnings
# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
# -pthreads: Solaris/gcc
# -mthreads: Mingw32/gcc, Lynx/gcc
# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
# doesn't hurt to check since this sometimes defines pthreads too;
# also defines -D_REENTRANT)
# ... -mt is also the pthreads flag for HP/aCC
# pthread: Linux, etcetera
# --thread-safe: KAI C++
# pthread-config: use pthread-config program (for GNU Pth library)
case "${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 -pthreads/-mt/
# -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="-pthreads pthread -mt -pthread $acx_pthread_flags"
;;
esac
if test x"$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 $flag])
PTHREAD_CXXFLAGS="$flag"
;;
pthread-config)
AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
if test x"$acx_pthread_config" = xno; then continue; fi
PTHREAD_CXXFLAGS="`pthread-config --cflags`"
PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
;;
*)
AC_MSG_CHECKING([for the pthreads library -l$flag])
PTHREAD_LIBS="-l$flag"
;;
esac
save_LIBS="$LIBS"
save_CXXFLAGS="$CXXFLAGS"
LIBS="$PTHREAD_LIBS $LIBS"
CXXFLAGS="$CXXFLAGS $PTHREAD_CXXFLAGS"
# Check for various functions. We must include pthread.h,
# since some functions may be macros. (On the Sequent, we
# need a special flag -Kthread to make this header compile.)
# We check for pthread_join because it is in -lpthread on IRIX
# while pthread_create is in libc. We check for pthread_attr_init
# due to DEC craziness with -lpthreads. We check for
# pthread_cleanup_push because it is one of the few pthread
# functions on Solaris that doesn't have a non-functional libc stub.
# We try pthread_create on general principles.
#
AC_TRY_LINK([#include <pthread.h>],
[pthread_t th; pthread_join(th, 0);
pthread_attr_init(0); pthread_cleanup_push(0, 0);
pthread_create(0,0,0,0); pthread_cleanup_pop(0);],
[acx_pthread_ok=yes])
LIBS="$save_LIBS"
CXXFLAGS="$save_CXXFLAGS"
AC_MSG_RESULT($acx_pthread_ok)
if test "x$acx_pthread_ok" = xyes; then
break;
fi
PTHREAD_LIBS=""
PTHREAD_CXXFLAGS=""
done
fi
# Various other checks:
if test "x$acx_pthread_ok" = xyes; then
save_LIBS="$LIBS"
LIBS="$PTHREAD_LIBS $LIBS"
save_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $PTHREAD_CXXFLAGS"
dnl # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
dnl AC_MSG_CHECKING([for joinable pthread attribute])
dnl attr_name=unknown
dnl for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
dnl AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
dnl [attr_name=$attr; break])
dnl done
dnl AC_MSG_RESULT($attr_name)
dnl if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
dnl AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
dnl [Define to necessary symbol if this constant
dnl uses a non-standard name on your system.])
dnl fi
AC_MSG_CHECKING([if more special flags are required for pthreads])
flag=no
case "${host_cpu}-${host_os}" in
*-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
*solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
esac
AC_MSG_RESULT(${flag})
if test "x$flag" != xno; then
PTHREAD_CXXFLAGS="$flag $PTHREAD_CXXFLAGS"
fi
LIBS="$save_LIBS"
CXXFLAGS="$save_CXXFLAGS"
dnl # More AIX lossage: must compile with xlC_r
dnl if test x"$GXX" != xyes; then
dnl AC_CHECK_PROGS(PTHREAD_CXX, xlC_r, ${CXX})
dnl else
dnl PTHREAD_CXX=$CXX
dnl fi
else
PTHREAD_CXX="$CXX"
fi
AC_SUBST(PTHREAD_LIBS)
AC_SUBST(PTHREAD_CXXFLAGS)
AC_SUBST(PTHREAD_CXX)
# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
if test x"$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
|
