ref: a1d4d588a866ce31b2abb3c89920ff4173e867ab
dir: /external/SDL2/src/hidapi/m4/ax_pthread.m4/
# ===========================================================================
# http://www.gnu.org/software/autoconf-archive/ax_pthread.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
#
# DESCRIPTION
#
# This macro figures out how to build C programs using POSIX threads. It
# sets the PTHREAD_LIBS output variable to the threads library and linker
# flags, and the PTHREAD_CFLAGS output variable to any special C compiler
# flags that are needed. (The user can also force certain compiler
# flags/libs to be tested by setting these environment variables.)
#
# Also sets PTHREAD_CC to any special C compiler that is needed for
# multi-threaded programs (defaults to the value of CC otherwise). (This
# is necessary on AIX to use the special cc_r compiler alias.)
#
# NOTE: You are assumed to not only compile your program with these flags,
# but also link it with them as well. e.g. you should link with
# $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
#
# If you are only building threads programs, you may wish to use these
# variables in your default LIBS, CFLAGS, and CC:
#
# LIBS="$PTHREAD_LIBS $LIBS"
# CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
# CC="$PTHREAD_CC"
#
# In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
# has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
# (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
#
# Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
# PTHREAD_PRIO_INHERIT symbol is defined when compiling with
# PTHREAD_CFLAGS.
#
# ACTION-IF-FOUND is a list of shell commands to run if a threads library
# is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
# is not found. If ACTION-IF-FOUND is not specified, the default action
# will define HAVE_PTHREAD.
#
# Please let the authors know if this macro fails on any platform, or if
# you have any other suggestions or comments. This macro was based on work
# by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
# from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
# Alejandro Forero Cuervo to the autoconf macro repository. We are also
# grateful for the helpful feedback of numerous users.
#
# Updated for Autoconf 2.68 by Daniel Richard G.
#
# LICENSE
#
# Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
# Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG>
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 18
AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
AC_DEFUN([AX_PTHREAD], [
AC_REQUIRE([AC_CANONICAL_HOST])
AC_LANG_PUSH([C])
ax_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=$PTHREAD_CFLAGS])
AC_TRY_LINK_FUNC(pthread_join, ax_pthread_ok=yes)
AC_MSG_RESULT($ax_pthread_ok)
if test x"$ax_pthread_ok" = xno; then
PTHREAD_LIBS=""
PTHREAD_CFLAGS=""
fi
LIBS="$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.
ax_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)
# ... -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_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:
ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
;;
darwin*)
ax_pthread_flags="-pthread $ax_pthread_flags"
;;
esac
if test x"$ax_pthread_ok" = xno; then
for flag in $ax_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(ax_pthread_config, pthread-config, yes, no)
if test x"$ax_pthread_config" = xno; then continue; fi
PTHREAD_CFLAGS="`pthread-config --cflags`"
PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
;;
*)
AC_MSG_CHECKING([for the pthreads library -l$flag])
PTHREAD_LIBS="-l$flag"
;;
esac
save_LIBS="$LIBS"
save_CFLAGS="$CFLAGS"
LIBS="$PTHREAD_LIBS $LIBS"
CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
# Check for various functions. We must include pthread.h,
# since some functions may be macros. (On the Sequent, we
# need a special flag -Kthread to make this header compile.)
# We check for pthread_join because it is in -lpthread on IRIX
# while pthread_create is in libc. We check for pthread_attr_init
# due to DEC craziness with -lpthreads. We check for
# pthread_cleanup_push because it is one of the few pthread
# functions on Solaris that doesn't have a non-functional libc stub.
# We try pthread_create on general principles.
AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
static void routine(void *a) { a = 0; }
static void *start_routine(void *a) { return a; }],
[pthread_t th; pthread_attr_t attr;
pthread_create(&th, 0, start_routine, 0);
pthread_join(th, 0);
pthread_attr_init(&attr);
pthread_cleanup_push(routine, 0);
pthread_cleanup_pop(0) /* ; */])],
[ax_pthread_ok=yes],
[])
LIBS="$save_LIBS"
CFLAGS="$save_CFLAGS"
AC_MSG_RESULT($ax_pthread_ok)
if test "x$ax_pthread_ok" = xyes; then
break;
fi
PTHREAD_LIBS=""
PTHREAD_CFLAGS=""
done
fi
# Various other checks:
if test "x$ax_pthread_ok" = xyes; then
save_LIBS="$LIBS"
LIBS="$PTHREAD_LIBS $LIBS"
save_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
# Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
AC_MSG_CHECKING([for joinable pthread attribute])
attr_name=unknown
for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
[int attr = $attr; return attr /* ; */])],
[attr_name=$attr; break],
[])
done
AC_MSG_RESULT($attr_name)
if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
[Define to necessary symbol if this constant
uses a non-standard name on your system.])
fi
AC_MSG_CHECKING([if more special flags are required for pthreads])
flag=no
case ${host_os} in
aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
osf* | hpux*) flag="-D_REENTRANT";;
solaris*)
if test "$GCC" = "yes"; then
flag="-D_REENTRANT"
else
flag="-mt -D_REENTRANT"
fi
;;
esac
AC_MSG_RESULT(${flag})
if test "x$flag" != xno; then
PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
fi
AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
ax_cv_PTHREAD_PRIO_INHERIT, [
AC_LINK_IFELSE([
AC_LANG_PROGRAM([[#include <pthread.h>]], [[int i = PTHREAD_PRIO_INHERIT;]])],
[ax_cv_PTHREAD_PRIO_INHERIT=yes],
[ax_cv_PTHREAD_PRIO_INHERIT=no])
])
AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], 1, [Have PTHREAD_PRIO_INHERIT.]))
LIBS="$save_LIBS"
CFLAGS="$save_CFLAGS"
# More AIX lossage: must compile with xlc_r or cc_r
if test x"$GCC" != xyes; then
AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
else
PTHREAD_CC=$CC
fi
else
PTHREAD_CC="$CC"
fi
AC_SUBST(PTHREAD_LIBS)
AC_SUBST(PTHREAD_CFLAGS)
AC_SUBST(PTHREAD_CC)
# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
if test x"$ax_pthread_ok" = xyes; then
ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
:
else
ax_pthread_ok=no
$2
fi
AC_LANG_POP
])dnl AX_PTHREAD