# =========================================================================== # https://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 and PTHREAD_CXX to any special C compiler that is # needed for multi-threaded programs (defaults to the value of CC # respectively CXX otherwise). (This is necessary on e.g. AIX to use the # special cc_r/CC_r compiler alias.) # # NOTE: You are assumed to not only compile your program with these flags, # but also to link with them as well. For example, you might link with # $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS # $PTHREAD_CXX $CXXFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS # # If you are only building threaded programs, you may wish to use these # variables in your default LIBS, CFLAGS, and CC: # # LIBS="$PTHREAD_LIBS $LIBS" # CFLAGS="$CFLAGS $PTHREAD_CFLAGS" # CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS" # CC="$PTHREAD_CC" # CXX="$PTHREAD_CXX" # # In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant # has a nonstandard name, this macro 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> # Copyright (c) 2019 Marc Stevens <marc.stevens@cwi.nl> # # 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 <https://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.
# We used to check for pthread.h first, but this fails if pthread.h # requires special compiler flags (e.g. on Tru64 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_CFLAGS$PTHREAD_LIBS" != "x"; then
ax_pthread_save_CC="$CC"
ax_pthread_save_CFLAGS="$CFLAGS"
ax_pthread_save_LIBS="$LIBS"
AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
AS_IF([test "x$PTHREAD_CXX" != "x"], [CXX="$PTHREAD_CXX"])
CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
LIBS="$PTHREAD_LIBS $LIBS"
AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
AC_MSG_RESULT([$ax_pthread_ok]) if test "x$ax_pthread_ok" = "xno"; then
PTHREAD_LIBS=""
PTHREAD_CFLAGS="" fi
CC="$ax_pthread_save_CC"
CFLAGS="$ax_pthread_save_CFLAGS"
LIBS="$ax_pthread_save_LIBS" 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 with a "," contain both # C compiler flags (before ",") and linker flags (after ","). Other items # starting with a "-" are C compiler flags, and remaining 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.
# 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) # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64 # (Note: HP C rejects this with "bad form for `-t' option") # -pthreads: Solaris/gcc (Note: HP C also rejects) # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it # doesn't hurt to check since this sometimes defines pthreads and # -D_REENTRANT too), HP C (must be checked before -lpthread, which # is present but should not be used directly; and before -mthreads, # because the compiler interprets this as "-mt" + "-hreads") # -mthreads: Mingw32/gcc, Lynx/gcc # pthread: Linux, etcetera # --thread-safe: KAI C++ # pthread-config: use pthread-config program (for GNU Pth library)
case $host_os in
freebsd*)
# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
# IBM z/OS requires a feature-test macro to be defined in order to # enable POSIX threads at all, so give the user a hint if this is # not set. (We don't define these ourselves, as they can affect # other portions of the system API in unpredictable ways.)
AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
[ # if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
AX_PTHREAD_ZOS_MISSING # endif
],
[AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
;;
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. (N.B.: 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 check first for the # standard Solaris way of linking pthreads (-mt -lpthread).
AC_CACHE_CHECK([whether $CC is Clang],
[ax_cv_PTHREAD_CLANG],
[ax_cv_PTHREAD_CLANG=no # Note that Autoconf sets GCC=yes for Clang as well as GCC if test "x$GCC" = "xyes"; then
AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
[/* Note: Clang 2.7 lacks __clang_[a-z]+__ */ # if defined(__clang__) && defined(__llvm__)
AX_PTHREAD_CC_IS_CLANG # endif
],
[ax_cv_PTHREAD_CLANG=yes]) fi
])
ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
# The presence of a feature test macro requesting re-entrant function # definitions is, on some systems, a strong hint that pthreads support is # correctly enabled
case $host_os in
darwin* | hpux* | linux* | osf* | solaris*)
ax_pthread_check_macro="_REENTRANT"
;;
if test "x$ax_pthread_ok" = "xno"; then for ax_pthread_try_flag in $ax_pthread_flags; do
case $ax_pthread_try_flag in
none)
AC_MSG_CHECKING([whether pthreads work without any flags])
;;
*,*)
PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"`
PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"`
AC_MSG_CHECKING([whether pthreads work with "$PTHREAD_CFLAGS" and "$PTHREAD_LIBS"])
;;
-*)
AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
PTHREAD_CFLAGS="$ax_pthread_try_flag"
;;
# 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.
# Clang needs special handling, because older versions handle the -pthread # option in a rather... idiosyncratic way
if test "x$ax_pthread_clang" = "xyes"; then
# Clang takes -pthread; it has never supported any other flag
# (Note 1: This will need to be revisited if a system that Clang # supports has POSIX threads in a separate library. This tends not # to be the way of modern systems, but it's conceivable.)
# (Note 2: On some systems, notably Darwin, -pthread is not needed # to get POSIX threads support; the API is always present and # active. We could reasonably leave PTHREAD_CFLAGS empty. But # -pthread does define _REENTRANT, and while the Darwin headers # ignore this macro, third-party headers might not.)
# However, older versions of Clang make a point of warning the user # that, in an invocation where only linking and no compilation is # taking place, the -pthread option has no effect ("argument unused # during compilation"). They expect -pthread to be passed in only # when source code is being compiled. # # Problem is, this is at odds with the way Automake and most other # C build frameworks function, which is that the same flags used in # compilation (CFLAGS) are also used in linking. Many systems # supported by AX_PTHREAD require exactly this for POSIX threads # support, and in fact it is often not straightforward to specify a # flag that is used only in the compilation phase and not in # linking. Such a scenario is extremely rare in practice. # # Even though use of the -pthread flag in linking would only print # a warning, this can be a nuisance for well-run software projects # that build with -Werror. So if the active version of Clang has # this misfeature, we search for an option to squash it.
AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
[ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
[ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown # Create an alternate version of $ac_link that compiles and # links in two steps (.c -> .o, .o -> exe) instead of one # (.c -> exe), because the warning occurs only in the second # step
ax_pthread_save_ac_link="$ac_link"
ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
ax_pthread_link_step=`AS_ECHO(["$ac_link"]) | sed "$ax_pthread_sed"`
ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
ax_pthread_save_CFLAGS="$CFLAGS" for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
ac_link="$ax_pthread_save_ac_link"
AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
[ac_link="$ax_pthread_2step_ac_link"
AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
[break])
]) done
ac_link="$ax_pthread_save_ac_link"
CFLAGS="$ax_pthread_save_CFLAGS"
AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
])
case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
no | unknown) ;;
*) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
esac
fi# $ax_pthread_clang = yes
# Various other checks: if test "x$ax_pthread_ok" = "xyes"; then
ax_pthread_save_CFLAGS="$CFLAGS"
ax_pthread_save_LIBS="$LIBS"
CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
LIBS="$PTHREAD_LIBS $LIBS"
# Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
AC_CACHE_CHECK([for joinable pthread attribute],
[ax_cv_PTHREAD_JOINABLE_ATTR],
[ax_cv_PTHREAD_JOINABLE_ATTR=unknown for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
[int attr = $ax_pthread_attr; return attr /* ; */])],
[ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
[]) done
])
AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
test "x$ax_pthread_joinable_attr_defined" != "xyes"],
[AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
[$ax_cv_PTHREAD_JOINABLE_ATTR],
[Define to necessary symbol if this constant
uses a non-standard name on your system.])
ax_pthread_joinable_attr_defined=yes
])
AC_CACHE_CHECK([whether more special flags are required for pthreads],
[ax_cv_PTHREAD_SPECIAL_FLAGS],
[ax_cv_PTHREAD_SPECIAL_FLAGS=no
case $host_os in
solaris*)
ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
;;
esac
])
AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
test "x$ax_pthread_special_flags_added" != "xyes"],
[PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
ax_pthread_special_flags_added=yes])
# More AIX lossage: compile with *_r variant if test "x$GCC" != "xyes"; then
case $host_os in
aix*)
AS_CASE(["x/$CC"],
[x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
[#handle absolute path differently from PATH based program lookup
AS_CASE(["x$CC"],
[x/*],
[
AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])
AS_IF([test "x${CXX}" != "x"], [AS_IF([AS_EXECUTABLE_P([${CXX}_r])],[PTHREAD_CXX="${CXX}_r"])])
],
[
AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])
AS_IF([test "x${CXX}" != "x"], [AC_CHECK_PROGS([PTHREAD_CXX],[${CXX}_r],[$CXX])])
]
)
])
;;
esac fi fi
test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: if test "x$ax_pthread_ok" = "xyes"; then
ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Defineif you have POSIX threads libraries and header files.])],[$1])
: else
ax_pthread_ok=no
$2 fi
AC_LANG_POP
])dnl AX_PTHREAD
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