1# =========================================================================== 2# https://www.gnu.org/software/autoconf-archive/ax_pthread.html 3# =========================================================================== 4# 5# SYNOPSIS 6# 7# AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 8# 9# DESCRIPTION 10# 11# This macro figures out how to build C programs using POSIX threads. It 12# sets the PTHREAD_LIBS output variable to the threads library and linker 13# flags, and the PTHREAD_CFLAGS output variable to any special C compiler 14# flags that are needed. (The user can also force certain compiler 15# flags/libs to be tested by setting these environment variables.) 16# 17# Also sets PTHREAD_CC to any special C compiler that is needed for 18# multi-threaded programs (defaults to the value of CC otherwise). (This 19# is necessary on AIX to use the special cc_r compiler alias.) 20# 21# NOTE: You are assumed to not only compile your program with these flags, 22# but also to link with them as well. For example, you might link with 23# $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS 24# 25# If you are only building threaded programs, you may wish to use these 26# variables in your default LIBS, CFLAGS, and CC: 27# 28# LIBS="$PTHREAD_LIBS $LIBS" 29# CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 30# CC="$PTHREAD_CC" 31# 32# In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant 33# has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to 34# that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). 35# 36# Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the 37# PTHREAD_PRIO_INHERIT symbol is defined when compiling with 38# PTHREAD_CFLAGS. 39# 40# ACTION-IF-FOUND is a list of shell commands to run if a threads library 41# is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it 42# is not found. If ACTION-IF-FOUND is not specified, the default action 43# will define HAVE_PTHREAD. 44# 45# Please let the authors know if this macro fails on any platform, or if 46# you have any other suggestions or comments. This macro was based on work 47# by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help 48# from M. Frigo), as well as ac_pthread and hb_pthread macros posted by 49# Alejandro Forero Cuervo to the autoconf macro repository. We are also 50# grateful for the helpful feedback of numerous users. 51# 52# Updated for Autoconf 2.68 by Daniel Richard G. 53# 54# LICENSE 55# 56# Copyright (c) 2008 Steven G. Johnson <[email protected]> 57# Copyright (c) 2011 Daniel Richard G. <[email protected]> 58# Copyright (c) 2019 Marc Stevens <[email protected]> 59# 60# This program is free software: you can redistribute it and/or modify it 61# under the terms of the GNU General Public License as published by the 62# Free Software Foundation, either version 3 of the License, or (at your 63# option) any later version. 64# 65# This program is distributed in the hope that it will be useful, but 66# WITHOUT ANY WARRANTY; without even the implied warranty of 67# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 68# Public License for more details. 69# 70# You should have received a copy of the GNU General Public License along 71# with this program. If not, see <https://www.gnu.org/licenses/>. 72# 73# As a special exception, the respective Autoconf Macro's copyright owner 74# gives unlimited permission to copy, distribute and modify the configure 75# scripts that are the output of Autoconf when processing the Macro. You 76# need not follow the terms of the GNU General Public License when using 77# or distributing such scripts, even though portions of the text of the 78# Macro appear in them. The GNU General Public License (GPL) does govern 79# all other use of the material that constitutes the Autoconf Macro. 80# 81# This special exception to the GPL applies to versions of the Autoconf 82# Macro released by the Autoconf Archive. When you make and distribute a 83# modified version of the Autoconf Macro, you may extend this special 84# exception to the GPL to apply to your modified version as well. 85 86#serial 27 87 88AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD]) 89AC_DEFUN([AX_PTHREAD], [ 90AC_REQUIRE([AC_CANONICAL_HOST]) 91AC_REQUIRE([AC_PROG_CC]) 92AC_REQUIRE([AC_PROG_SED]) 93AC_LANG_PUSH([C]) 94ax_pthread_ok=no 95 96# We used to check for pthread.h first, but this fails if pthread.h 97# requires special compiler flags (e.g. on Tru64 or Sequent). 98# It gets checked for in the link test anyway. 99 100# First of all, check if the user has set any of the PTHREAD_LIBS, 101# etcetera environment variables, and if threads linking works using 102# them: 103if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then 104 ax_pthread_save_CC="$CC" 105 ax_pthread_save_CFLAGS="$CFLAGS" 106 ax_pthread_save_LIBS="$LIBS" 107 AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"]) 108 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 109 LIBS="$PTHREAD_LIBS $LIBS" 110 AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS]) 111 AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes]) 112 AC_MSG_RESULT([$ax_pthread_ok]) 113 if test "x$ax_pthread_ok" = "xno"; then 114 PTHREAD_LIBS="" 115 PTHREAD_CFLAGS="" 116 fi 117 CC="$ax_pthread_save_CC" 118 CFLAGS="$ax_pthread_save_CFLAGS" 119 LIBS="$ax_pthread_save_LIBS" 120fi 121 122# We must check for the threads library under a number of different 123# names; the ordering is very important because some systems 124# (e.g. DEC) have both -lpthread and -lpthreads, where one of the 125# libraries is broken (non-POSIX). 126 127# Create a list of thread flags to try. Items with a "," contain both 128# C compiler flags (before ",") and linker flags (after ","). Other items 129# starting with a "-" are C compiler flags, and remaining items are 130# library names, except for "none" which indicates that we try without 131# any flags at all, and "pthread-config" which is a program returning 132# the flags for the Pth emulation library. 133 134ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" 135 136# The ordering *is* (sometimes) important. Some notes on the 137# individual items follow: 138 139# pthreads: AIX (must check this before -lpthread) 140# none: in case threads are in libc; should be tried before -Kthread and 141# other compiler flags to prevent continual compiler warnings 142# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) 143# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64 144# (Note: HP C rejects this with "bad form for `-t' option") 145# -pthreads: Solaris/gcc (Note: HP C also rejects) 146# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it 147# doesn't hurt to check since this sometimes defines pthreads and 148# -D_REENTRANT too), HP C (must be checked before -lpthread, which 149# is present but should not be used directly; and before -mthreads, 150# because the compiler interprets this as "-mt" + "-hreads") 151# -mthreads: Mingw32/gcc, Lynx/gcc 152# pthread: Linux, etcetera 153# --thread-safe: KAI C++ 154# pthread-config: use pthread-config program (for GNU Pth library) 155 156case $host_os in 157 158 freebsd*) 159 160 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) 161 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) 162 163 ax_pthread_flags="-kthread lthread $ax_pthread_flags" 164 ;; 165 166 hpux*) 167 168 # From the cc(1) man page: "[-mt] Sets various -D flags to enable 169 # multi-threading and also sets -lpthread." 170 171 ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags" 172 ;; 173 174 openedition*) 175 176 # IBM z/OS requires a feature-test macro to be defined in order to 177 # enable POSIX threads at all, so give the user a hint if this is 178 # not set. (We don't define these ourselves, as they can affect 179 # other portions of the system API in unpredictable ways.) 180 181 AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING], 182 [ 183# if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS) 184 AX_PTHREAD_ZOS_MISSING 185# endif 186 ], 187 [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])]) 188 ;; 189 190 solaris*) 191 192 # On Solaris (at least, for some versions), libc contains stubbed 193 # (non-functional) versions of the pthreads routines, so link-based 194 # tests will erroneously succeed. (N.B.: The stubs are missing 195 # pthread_cleanup_push, or rather a function called by this macro, 196 # so we could check for that, but who knows whether they'll stub 197 # that too in a future libc.) So we'll check first for the 198 # standard Solaris way of linking pthreads (-mt -lpthread). 199 200 ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags" 201 ;; 202esac 203 204# Are we compiling with Clang? 205 206AC_CACHE_CHECK([whether $CC is Clang], 207 [ax_cv_PTHREAD_CLANG], 208 [ax_cv_PTHREAD_CLANG=no 209 # Note that Autoconf sets GCC=yes for Clang as well as GCC 210 if test "x$GCC" = "xyes"; then 211 AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG], 212 [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */ 213# if defined(__clang__) && defined(__llvm__) 214 AX_PTHREAD_CC_IS_CLANG 215# endif 216 ], 217 [ax_cv_PTHREAD_CLANG=yes]) 218 fi 219 ]) 220ax_pthread_clang="$ax_cv_PTHREAD_CLANG" 221 222 223# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC) 224 225# Note that for GCC and Clang -pthread generally implies -lpthread, 226# except when -nostdlib is passed. 227# This is problematic using libtool to build C++ shared libraries with pthread: 228# [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460 229# [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333 230# [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555 231# To solve this, first try -pthread together with -lpthread for GCC 232 233AS_IF([test "x$GCC" = "xyes"], 234 [ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"]) 235 236# Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first 237 238AS_IF([test "x$ax_pthread_clang" = "xyes"], 239 [ax_pthread_flags="-pthread,-lpthread -pthread"]) 240 241 242# The presence of a feature test macro requesting re-entrant function 243# definitions is, on some systems, a strong hint that pthreads support is 244# correctly enabled 245 246case $host_os in 247 darwin* | hpux* | linux* | osf* | solaris*) 248 ax_pthread_check_macro="_REENTRANT" 249 ;; 250 251 aix*) 252 ax_pthread_check_macro="_THREAD_SAFE" 253 ;; 254 255 *) 256 ax_pthread_check_macro="--" 257 ;; 258esac 259AS_IF([test "x$ax_pthread_check_macro" = "x--"], 260 [ax_pthread_check_cond=0], 261 [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"]) 262 263 264if test "x$ax_pthread_ok" = "xno"; then 265for ax_pthread_try_flag in $ax_pthread_flags; do 266 267 case $ax_pthread_try_flag in 268 none) 269 AC_MSG_CHECKING([whether pthreads work without any flags]) 270 ;; 271 272 *,*) 273 PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"` 274 PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"` 275 AC_MSG_CHECKING([whether pthreads work with "$PTHREAD_CFLAGS" and "$PTHREAD_LIBS"]) 276 ;; 277 278 -*) 279 AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag]) 280 PTHREAD_CFLAGS="$ax_pthread_try_flag" 281 ;; 282 283 pthread-config) 284 AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no]) 285 AS_IF([test "x$ax_pthread_config" = "xno"], [continue]) 286 PTHREAD_CFLAGS="`pthread-config --cflags`" 287 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" 288 ;; 289 290 *) 291 AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag]) 292 PTHREAD_LIBS="-l$ax_pthread_try_flag" 293 ;; 294 esac 295 296 ax_pthread_save_CFLAGS="$CFLAGS" 297 ax_pthread_save_LIBS="$LIBS" 298 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 299 LIBS="$PTHREAD_LIBS $LIBS" 300 301 # Check for various functions. We must include pthread.h, 302 # since some functions may be macros. (On the Sequent, we 303 # need a special flag -Kthread to make this header compile.) 304 # We check for pthread_join because it is in -lpthread on IRIX 305 # while pthread_create is in libc. We check for pthread_attr_init 306 # due to DEC craziness with -lpthreads. We check for 307 # pthread_cleanup_push because it is one of the few pthread 308 # functions on Solaris that doesn't have a non-functional libc stub. 309 # We try pthread_create on general principles. 310 311 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h> 312# if $ax_pthread_check_cond 313# error "$ax_pthread_check_macro must be defined" 314# endif 315 static void *some_global = NULL; 316 static void routine(void *a) 317 { 318 /* To avoid any unused-parameter or 319 unused-but-set-parameter warning. */ 320 some_global = a; 321 } 322 static void *start_routine(void *a) { return a; }], 323 [pthread_t th; pthread_attr_t attr; 324 pthread_create(&th, 0, start_routine, 0); 325 pthread_join(th, 0); 326 pthread_attr_init(&attr); 327 pthread_cleanup_push(routine, 0); 328 pthread_cleanup_pop(0) /* ; */])], 329 [ax_pthread_ok=yes], 330 []) 331 332 CFLAGS="$ax_pthread_save_CFLAGS" 333 LIBS="$ax_pthread_save_LIBS" 334 335 AC_MSG_RESULT([$ax_pthread_ok]) 336 AS_IF([test "x$ax_pthread_ok" = "xyes"], [break]) 337 338 PTHREAD_LIBS="" 339 PTHREAD_CFLAGS="" 340done 341fi 342 343 344# Clang needs special handling, because older versions handle the -pthread 345# option in a rather... idiosyncratic way 346 347if test "x$ax_pthread_clang" = "xyes"; then 348 349 # Clang takes -pthread; it has never supported any other flag 350 351 # (Note 1: This will need to be revisited if a system that Clang 352 # supports has POSIX threads in a separate library. This tends not 353 # to be the way of modern systems, but it's conceivable.) 354 355 # (Note 2: On some systems, notably Darwin, -pthread is not needed 356 # to get POSIX threads support; the API is always present and 357 # active. We could reasonably leave PTHREAD_CFLAGS empty. But 358 # -pthread does define _REENTRANT, and while the Darwin headers 359 # ignore this macro, third-party headers might not.) 360 361 # However, older versions of Clang make a point of warning the user 362 # that, in an invocation where only linking and no compilation is 363 # taking place, the -pthread option has no effect ("argument unused 364 # during compilation"). They expect -pthread to be passed in only 365 # when source code is being compiled. 366 # 367 # Problem is, this is at odds with the way Automake and most other 368 # C build frameworks function, which is that the same flags used in 369 # compilation (CFLAGS) are also used in linking. Many systems 370 # supported by AX_PTHREAD require exactly this for POSIX threads 371 # support, and in fact it is often not straightforward to specify a 372 # flag that is used only in the compilation phase and not in 373 # linking. Such a scenario is extremely rare in practice. 374 # 375 # Even though use of the -pthread flag in linking would only print 376 # a warning, this can be a nuisance for well-run software projects 377 # that build with -Werror. So if the active version of Clang has 378 # this misfeature, we search for an option to squash it. 379 380 AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread], 381 [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG], 382 [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown 383 # Create an alternate version of $ac_link that compiles and 384 # links in two steps (.c -> .o, .o -> exe) instead of one 385 # (.c -> exe), because the warning occurs only in the second 386 # step 387 ax_pthread_save_ac_link="$ac_link" 388 ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g' 389 ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"` 390 ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)" 391 ax_pthread_save_CFLAGS="$CFLAGS" 392 for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do 393 AS_IF([test "x$ax_pthread_try" = "xunknown"], [break]) 394 CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS" 395 ac_link="$ax_pthread_save_ac_link" 396 AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], 397 [ac_link="$ax_pthread_2step_ac_link" 398 AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])], 399 [break]) 400 ]) 401 done 402 ac_link="$ax_pthread_save_ac_link" 403 CFLAGS="$ax_pthread_save_CFLAGS" 404 AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no]) 405 ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try" 406 ]) 407 408 case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in 409 no | unknown) ;; 410 *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;; 411 esac 412 413fi # $ax_pthread_clang = yes 414 415 416 417# Various other checks: 418if test "x$ax_pthread_ok" = "xyes"; then 419 ax_pthread_save_CFLAGS="$CFLAGS" 420 ax_pthread_save_LIBS="$LIBS" 421 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 422 LIBS="$PTHREAD_LIBS $LIBS" 423 424 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. 425 AC_CACHE_CHECK([for joinable pthread attribute], 426 [ax_cv_PTHREAD_JOINABLE_ATTR], 427 [ax_cv_PTHREAD_JOINABLE_ATTR=unknown 428 for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do 429 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>], 430 [int attr = $ax_pthread_attr; return attr /* ; */])], 431 [ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break], 432 []) 433 done 434 ]) 435 AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \ 436 test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \ 437 test "x$ax_pthread_joinable_attr_defined" != "xyes"], 438 [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], 439 [$ax_cv_PTHREAD_JOINABLE_ATTR], 440 [Define to necessary symbol if this constant 441 uses a non-standard name on your system.]) 442 ax_pthread_joinable_attr_defined=yes 443 ]) 444 445 AC_CACHE_CHECK([whether more special flags are required for pthreads], 446 [ax_cv_PTHREAD_SPECIAL_FLAGS], 447 [ax_cv_PTHREAD_SPECIAL_FLAGS=no 448 case $host_os in 449 solaris*) 450 ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS" 451 ;; 452 esac 453 ]) 454 AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \ 455 test "x$ax_pthread_special_flags_added" != "xyes"], 456 [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS" 457 ax_pthread_special_flags_added=yes]) 458 459 AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT], 460 [ax_cv_PTHREAD_PRIO_INHERIT], 461 [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]], 462 [[int i = PTHREAD_PRIO_INHERIT; 463 return i;]])], 464 [ax_cv_PTHREAD_PRIO_INHERIT=yes], 465 [ax_cv_PTHREAD_PRIO_INHERIT=no]) 466 ]) 467 AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \ 468 test "x$ax_pthread_prio_inherit_defined" != "xyes"], 469 [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.]) 470 ax_pthread_prio_inherit_defined=yes 471 ]) 472 473 CFLAGS="$ax_pthread_save_CFLAGS" 474 LIBS="$ax_pthread_save_LIBS" 475 476 # More AIX lossage: compile with *_r variant 477 if test "x$GCC" != "xyes"; then 478 case $host_os in 479 aix*) 480 AS_CASE(["x/$CC"], 481 [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6], 482 [#handle absolute path differently from PATH based program lookup 483 AS_CASE(["x$CC"], 484 [x/*], 485 [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])], 486 [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])]) 487 ;; 488 esac 489 fi 490fi 491 492test -n "$PTHREAD_CC" || PTHREAD_CC="$CC" 493 494AC_SUBST([PTHREAD_LIBS]) 495AC_SUBST([PTHREAD_CFLAGS]) 496AC_SUBST([PTHREAD_CC]) 497 498# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: 499if test "x$ax_pthread_ok" = "xyes"; then 500 ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1]) 501 : 502else 503 ax_pthread_ok=no 504 $2 505fi 506AC_LANG_POP 507])dnl AX_PTHREAD 508