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