ax_pthread.m4 revision 1.1.1.2
1# SPDX-License-Identifier: GPL-3.0-or-later WITH Autoconf-exception-3.0 2# 3# =========================================================================== 4# https://www.gnu.org/software/autoconf-archive/ax_pthread.html 5# =========================================================================== 6# 7# SYNOPSIS 8# 9# AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 10# 11# DESCRIPTION 12# 13# This macro figures out how to build C programs using POSIX threads. It 14# sets the PTHREAD_LIBS output variable to the threads library and linker 15# flags, and the PTHREAD_CFLAGS output variable to any special C compiler 16# flags that are needed. (The user can also force certain compiler 17# flags/libs to be tested by setting these environment variables.) 18# 19# Also sets PTHREAD_CC to any special C compiler that is needed for 20# multi-threaded programs (defaults to the value of CC otherwise). (This 21# is necessary on AIX to use the special cc_r compiler alias.) 22# 23# NOTE: You are assumed to not only compile your program with these flags, 24# but also to link with them as well. For example, you might link with 25# $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS 26# 27# If you are only building threaded programs, you may wish to use these 28# variables in your default LIBS, CFLAGS, and CC: 29# 30# LIBS="$PTHREAD_LIBS $LIBS" 31# CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 32# CC="$PTHREAD_CC" 33# 34# In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant 35# has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to 36# that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). 37# 38# Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the 39# PTHREAD_PRIO_INHERIT symbol is defined when compiling with 40# PTHREAD_CFLAGS. 41# 42# ACTION-IF-FOUND is a list of shell commands to run if a threads library 43# is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it 44# is not found. If ACTION-IF-FOUND is not specified, the default action 45# will define HAVE_PTHREAD. 46# 47# Please let the authors know if this macro fails on any platform, or if 48# you have any other suggestions or comments. This macro was based on work 49# by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help 50# from M. Frigo), as well as ac_pthread and hb_pthread macros posted by 51# Alejandro Forero Cuervo to the autoconf macro repository. We are also 52# grateful for the helpful feedback of numerous users. 53# 54# Updated for Autoconf 2.68 by Daniel Richard G. 55# 56# LICENSE 57# 58# Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu> 59# Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG> 60# 61# This program is free software: you can redistribute it and/or modify it 62# under the terms of the GNU General Public License as published by the 63# Free Software Foundation, either version 3 of the License, or (at your 64# option) any later version. 65# 66# This program is distributed in the hope that it will be useful, but 67# WITHOUT ANY WARRANTY; without even the implied warranty of 68# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 69# Public License for more details. 70# 71# You should have received a copy of the GNU General Public License along 72# with this program. If not, see <https://www.gnu.org/licenses/>. 73# 74# As a special exception, the respective Autoconf Macro's copyright owner 75# gives unlimited permission to copy, distribute and modify the configure 76# scripts that are the output of Autoconf when processing the Macro. You 77# need not follow the terms of the GNU General Public License when using 78# or distributing such scripts, even though portions of the text of the 79# Macro appear in them. The GNU General Public License (GPL) does govern 80# all other use of the material that constitutes the Autoconf Macro. 81# 82# This special exception to the GPL applies to versions of the Autoconf 83# Macro released by the Autoconf Archive. When you make and distribute a 84# modified version of the Autoconf Macro, you may extend this special 85# exception to the GPL to apply to your modified version as well. 86 87#serial 24 88 89AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD]) 90AC_DEFUN([AX_PTHREAD], [ 91AC_REQUIRE([AC_CANONICAL_HOST]) 92AC_REQUIRE([AC_PROG_CC]) 93AC_REQUIRE([AC_PROG_SED]) 94AC_LANG_PUSH([C]) 95ax_pthread_ok=no 96 97# We used to check for pthread.h first, but this fails if pthread.h 98# requires special compiler flags (e.g. on Tru64 or Sequent). 99# It gets checked for in the link test anyway. 100 101# First of all, check if the user has set any of the PTHREAD_LIBS, 102# etcetera environment variables, and if threads linking works using 103# them: 104if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then 105 ax_pthread_save_CC="$CC" 106 ax_pthread_save_CFLAGS="$CFLAGS" 107 ax_pthread_save_LIBS="$LIBS" 108 AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"]) 109 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 110 LIBS="$PTHREAD_LIBS $LIBS" 111 AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS]) 112 AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes]) 113 AC_MSG_RESULT([$ax_pthread_ok]) 114 if test "x$ax_pthread_ok" = "xno"; then 115 PTHREAD_LIBS="" 116 PTHREAD_CFLAGS="" 117 fi 118 CC="$ax_pthread_save_CC" 119 CFLAGS="$ax_pthread_save_CFLAGS" 120 LIBS="$ax_pthread_save_LIBS" 121fi 122 123# We must check for the threads library under a number of different 124# names; the ordering is very important because some systems 125# (e.g. DEC) have both -lpthread and -lpthreads, where one of the 126# libraries is broken (non-POSIX). 127 128# Create a list of thread flags to try. Items starting with a "-" are 129# C compiler flags, and other items are library names, except for "none" 130# which indicates that we try without any flags at all, and "pthread-config" 131# which is a program returning the flags for the Pth emulation library. 132 133ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" 134 135# The ordering *is* (sometimes) important. Some notes on the 136# individual items follow: 137 138# pthreads: AIX (must check this before -lpthread) 139# none: in case threads are in libc; should be tried before -Kthread and 140# other compiler flags to prevent continual compiler warnings 141# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) 142# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64 143# (Note: HP C rejects this with "bad form for `-t' option") 144# -pthreads: Solaris/gcc (Note: HP C also rejects) 145# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it 146# doesn't hurt to check since this sometimes defines pthreads and 147# -D_REENTRANT too), HP C (must be checked before -lpthread, which 148# is present but should not be used directly; and before -mthreads, 149# because the compiler interprets this as "-mt" + "-hreads") 150# -mthreads: Mingw32/gcc, Lynx/gcc 151# pthread: Linux, etcetera 152# --thread-safe: KAI C++ 153# pthread-config: use pthread-config program (for GNU Pth library) 154 155case $host_os in 156 157 freebsd*) 158 159 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) 160 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) 161 162 ax_pthread_flags="-kthread lthread $ax_pthread_flags" 163 ;; 164 165 hpux*) 166 167 # From the cc(1) man page: "[-mt] Sets various -D flags to enable 168 # multi-threading and also sets -lpthread." 169 170 ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags" 171 ;; 172 173 openedition*) 174 175 # IBM z/OS requires a feature-test macro to be defined in order to 176 # enable POSIX threads at all, so give the user a hint if this is 177 # not set. (We don't define these ourselves, as they can affect 178 # other portions of the system API in unpredictable ways.) 179 180 AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING], 181 [ 182# if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS) 183 AX_PTHREAD_ZOS_MISSING 184# endif 185 ], 186 [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])]) 187 ;; 188 189 solaris*) 190 191 # On Solaris (at least, for some versions), libc contains stubbed 192 # (non-functional) versions of the pthreads routines, so link-based 193 # tests will erroneously succeed. (N.B.: The stubs are missing 194 # pthread_cleanup_push, or rather a function called by this macro, 195 # so we could check for that, but who knows whether they'll stub 196 # that too in a future libc.) So we'll check first for the 197 # standard Solaris way of linking pthreads (-mt -lpthread). 198 199 ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags" 200 ;; 201esac 202 203# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC) 204 205AS_IF([test "x$GCC" = "xyes"], 206 [ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"]) 207 208# The presence of a feature test macro requesting re-entrant function 209# definitions is, on some systems, a strong hint that pthreads support is 210# correctly enabled 211 212case $host_os in 213 darwin* | hpux* | linux* | osf* | solaris*) 214 ax_pthread_check_macro="_REENTRANT" 215 ;; 216 217 aix*) 218 ax_pthread_check_macro="_THREAD_SAFE" 219 ;; 220 221 *) 222 ax_pthread_check_macro="--" 223 ;; 224esac 225AS_IF([test "x$ax_pthread_check_macro" = "x--"], 226 [ax_pthread_check_cond=0], 227 [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"]) 228 229# Are we compiling with Clang? 230 231AC_CACHE_CHECK([whether $CC is Clang], 232 [ax_cv_PTHREAD_CLANG], 233 [ax_cv_PTHREAD_CLANG=no 234 # Note that Autoconf sets GCC=yes for Clang as well as GCC 235 if test "x$GCC" = "xyes"; then 236 AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG], 237 [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */ 238# if defined(__clang__) && defined(__llvm__) 239 AX_PTHREAD_CC_IS_CLANG 240# endif 241 ], 242 [ax_cv_PTHREAD_CLANG=yes]) 243 fi 244 ]) 245ax_pthread_clang="$ax_cv_PTHREAD_CLANG" 246 247ax_pthread_clang_warning=no 248 249# Clang needs special handling, because older versions handle the -pthread 250# option in a rather... idiosyncratic way 251 252if test "x$ax_pthread_clang" = "xyes"; then 253 254 # Clang takes -pthread; it has never supported any other flag 255 256 # (Note 1: This will need to be revisited if a system that Clang 257 # supports has POSIX threads in a separate library. This tends not 258 # to be the way of modern systems, but it's conceivable.) 259 260 # (Note 2: On some systems, notably Darwin, -pthread is not needed 261 # to get POSIX threads support; the API is always present and 262 # active. We could reasonably leave PTHREAD_CFLAGS empty. But 263 # -pthread does define _REENTRANT, and while the Darwin headers 264 # ignore this macro, third-party headers might not.) 265 266 PTHREAD_CFLAGS="-pthread" 267 PTHREAD_LIBS= 268 269 ax_pthread_ok=yes 270 271 # However, older versions of Clang make a point of warning the user 272 # that, in an invocation where only linking and no compilation is 273 # taking place, the -pthread option has no effect ("argument unused 274 # during compilation"). They expect -pthread to be passed in only 275 # when source code is being compiled. 276 # 277 # Problem is, this is at odds with the way Automake and most other 278 # C build frameworks function, which is that the same flags used in 279 # compilation (CFLAGS) are also used in linking. Many systems 280 # supported by AX_PTHREAD require exactly this for POSIX threads 281 # support, and in fact it is often not straightforward to specify a 282 # flag that is used only in the compilation phase and not in 283 # linking. Such a scenario is extremely rare in practice. 284 # 285 # Even though use of the -pthread flag in linking would only print 286 # a warning, this can be a nuisance for well-run software projects 287 # that build with -Werror. So if the active version of Clang has 288 # this misfeature, we search for an option to squash it. 289 290 AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread], 291 [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG], 292 [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown 293 # Create an alternate version of $ac_link that compiles and 294 # links in two steps (.c -> .o, .o -> exe) instead of one 295 # (.c -> exe), because the warning occurs only in the second 296 # step 297 ax_pthread_save_ac_link="$ac_link" 298 ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g' 299 ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"` 300 ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)" 301 ax_pthread_save_CFLAGS="$CFLAGS" 302 for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do 303 AS_IF([test "x$ax_pthread_try" = "xunknown"], [break]) 304 CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS" 305 ac_link="$ax_pthread_save_ac_link" 306 AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], 307 [ac_link="$ax_pthread_2step_ac_link" 308 AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], 309 [break]) 310 ]) 311 done 312 ac_link="$ax_pthread_save_ac_link" 313 CFLAGS="$ax_pthread_save_CFLAGS" 314 AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no]) 315 ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try" 316 ]) 317 318 case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in 319 no | unknown) ;; 320 *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;; 321 esac 322 323fi # $ax_pthread_clang = yes 324 325if test "x$ax_pthread_ok" = "xno"; then 326for ax_pthread_try_flag in $ax_pthread_flags; do 327 328 case $ax_pthread_try_flag in 329 none) 330 AC_MSG_CHECKING([whether pthreads work without any flags]) 331 ;; 332 333 -mt,pthread) 334 AC_MSG_CHECKING([whether pthreads work with -mt -lpthread]) 335 PTHREAD_CFLAGS="-mt" 336 PTHREAD_LIBS="-lpthread" 337 ;; 338 339 -*) 340 AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag]) 341 PTHREAD_CFLAGS="$ax_pthread_try_flag" 342 ;; 343 344 pthread-config) 345 AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no]) 346 AS_IF([test "x$ax_pthread_config" = "xno"], [continue]) 347 PTHREAD_CFLAGS="`pthread-config --cflags`" 348 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" 349 ;; 350 351 *) 352 AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag]) 353 PTHREAD_LIBS="-l$ax_pthread_try_flag" 354 ;; 355 esac 356 357 ax_pthread_save_CFLAGS="$CFLAGS" 358 ax_pthread_save_LIBS="$LIBS" 359 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 360 LIBS="$PTHREAD_LIBS $LIBS" 361 362 # Check for various functions. We must include pthread.h, 363 # since some functions may be macros. (On the Sequent, we 364 # need a special flag -Kthread to make this header compile.) 365 # We check for pthread_join because it is in -lpthread on IRIX 366 # while pthread_create is in libc. We check for pthread_attr_init 367 # due to DEC craziness with -lpthreads. We check for 368 # pthread_cleanup_push because it is one of the few pthread 369 # functions on Solaris that doesn't have a non-functional libc stub. 370 # We try pthread_create on general principles. 371 372 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h> 373# if $ax_pthread_check_cond 374# error "$ax_pthread_check_macro must be defined" 375# endif 376 static void routine(void *a) { a = 0; } 377 static void *start_routine(void *a) { return a; }], 378 [pthread_t th; pthread_attr_t attr; 379 pthread_create(&th, 0, start_routine, 0); 380 pthread_join(th, 0); 381 pthread_attr_init(&attr); 382 pthread_cleanup_push(routine, 0); 383 pthread_cleanup_pop(0) /* ; */])], 384 [ax_pthread_ok=yes], 385 []) 386 387 CFLAGS="$ax_pthread_save_CFLAGS" 388 LIBS="$ax_pthread_save_LIBS" 389 390 AC_MSG_RESULT([$ax_pthread_ok]) 391 AS_IF([test "x$ax_pthread_ok" = "xyes"], [break]) 392 393 PTHREAD_LIBS="" 394 PTHREAD_CFLAGS="" 395done 396fi 397 398# Various other checks: 399if test "x$ax_pthread_ok" = "xyes"; then 400 ax_pthread_save_CFLAGS="$CFLAGS" 401 ax_pthread_save_LIBS="$LIBS" 402 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 403 LIBS="$PTHREAD_LIBS $LIBS" 404 405 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. 406 AC_CACHE_CHECK([for joinable pthread attribute], 407 [ax_cv_PTHREAD_JOINABLE_ATTR], 408 [ax_cv_PTHREAD_JOINABLE_ATTR=unknown 409 for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do 410 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>], 411 [int attr = $ax_pthread_attr; return attr /* ; */])], 412 [ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break], 413 []) 414 done 415 ]) 416 AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \ 417 test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \ 418 test "x$ax_pthread_joinable_attr_defined" != "xyes"], 419 [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], 420 [$ax_cv_PTHREAD_JOINABLE_ATTR], 421 [Define to necessary symbol if this constant 422 uses a non-standard name on your system.]) 423 ax_pthread_joinable_attr_defined=yes 424 ]) 425 426 AC_CACHE_CHECK([whether more special flags are required for pthreads], 427 [ax_cv_PTHREAD_SPECIAL_FLAGS], 428 [ax_cv_PTHREAD_SPECIAL_FLAGS=no 429 case $host_os in 430 solaris*) 431 ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS" 432 ;; 433 esac 434 ]) 435 AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \ 436 test "x$ax_pthread_special_flags_added" != "xyes"], 437 [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS" 438 ax_pthread_special_flags_added=yes]) 439 440 AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT], 441 [ax_cv_PTHREAD_PRIO_INHERIT], 442 [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], 443 [[int i = PTHREAD_PRIO_INHERIT;]])], 444 [ax_cv_PTHREAD_PRIO_INHERIT=yes], 445 [ax_cv_PTHREAD_PRIO_INHERIT=no]) 446 ]) 447 AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \ 448 test "x$ax_pthread_prio_inherit_defined" != "xyes"], 449 [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.]) 450 ax_pthread_prio_inherit_defined=yes 451 ]) 452 453 CFLAGS="$ax_pthread_save_CFLAGS" 454 LIBS="$ax_pthread_save_LIBS" 455 456 # More AIX lossage: compile with *_r variant 457 if test "x$GCC" != "xyes"; then 458 case $host_os in 459 aix*) 460 AS_CASE(["x/$CC"], 461 [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6], 462 [#handle absolute path differently from PATH based program lookup 463 AS_CASE(["x$CC"], 464 [x/*], 465 [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])], 466 [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])]) 467 ;; 468 esac 469 fi 470fi 471 472test -n "$PTHREAD_CC" || PTHREAD_CC="$CC" 473 474AC_SUBST([PTHREAD_LIBS]) 475AC_SUBST([PTHREAD_CFLAGS]) 476AC_SUBST([PTHREAD_CC]) 477 478# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: 479if test "x$ax_pthread_ok" = "xyes"; then 480 ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1]) 481 : 482else 483 ax_pthread_ok=no 484 $2 485fi 486AC_LANG_POP 487])dnl AX_PTHREAD 488