1 dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 2 dnl 3 dnl @summary figure out how to build C programs using POSIX threads 4 dnl 5 dnl This macro figures out how to build C programs using POSIX threads. 6 dnl It sets the PTHREAD_LIBS output variable to the threads library and 7 dnl linker flags, and the PTHREAD_CFLAGS output variable to any special 8 dnl C compiler flags that are needed. (The user can also force certain 9 dnl compiler flags/libs to be tested by setting these environment 10 dnl variables.) 11 dnl 12 dnl Also sets PTHREAD_CC to any special C compiler that is needed for 13 dnl multi-threaded programs (defaults to the value of CC otherwise). 14 dnl (This is necessary on AIX to use the special cc_r compiler alias.) 15 dnl 16 dnl NOTE: You are assumed to not only compile your program with these 17 dnl flags, but also link it with them as well. e.g. you should link 18 dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS 19 dnl $LIBS 20 dnl 21 dnl If you are only building threads programs, you may wish to use 22 dnl these variables in your default LIBS, CFLAGS, and CC: 23 dnl 24 dnl LIBS="$PTHREAD_LIBS $LIBS" 25 dnl CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 26 dnl CC="$PTHREAD_CC" 27 dnl 28 dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute 29 dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to 30 dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). 31 dnl 32 dnl ACTION-IF-FOUND is a list of shell commands to run if a threads 33 dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to 34 dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the 35 dnl default action will define HAVE_PTHREAD. 36 dnl 37 dnl Please let the authors know if this macro fails on any platform, or 38 dnl if you have any other suggestions or comments. This macro was based 39 dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with 40 dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros 41 dnl posted by Alejandro Forero Cuervo to the autoconf macro repository. 42 dnl We are also grateful for the helpful feedback of numerous users. 43 dnl 44 dnl @category InstalledPackages 45 dnl @author Steven G. Johnson <stevenj (a] alum.mit.edu> 46 dnl @version 2006-05-29 47 dnl @license GPLWithACException 48 dnl 49 dnl Checks for GCC shared/pthread inconsistency based on work by 50 dnl Marcin Owsiany <marcin (a] owsiany.pl> 51 52 53 AC_DEFUN([ACX_PTHREAD], [ 54 AC_REQUIRE([AC_CANONICAL_HOST]) 55 AC_LANG_SAVE 56 AC_LANG_C 57 acx_pthread_ok=no 58 59 # We used to check for pthread.h first, but this fails if pthread.h 60 # requires special compiler flags (e.g. on True64 or Sequent). 61 # It gets checked for in the link test anyway. 62 63 # First of all, check if the user has set any of the PTHREAD_LIBS, 64 # etcetera environment variables, and if threads linking works using 65 # them: 66 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then 67 save_CFLAGS="$CFLAGS" 68 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 69 save_LIBS="$LIBS" 70 LIBS="$PTHREAD_LIBS $LIBS" 71 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS]) 72 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes) 73 AC_MSG_RESULT($acx_pthread_ok) 74 if test x"$acx_pthread_ok" = xno; then 75 PTHREAD_LIBS="" 76 PTHREAD_CFLAGS="" 77 fi 78 LIBS="$save_LIBS" 79 CFLAGS="$save_CFLAGS" 80 fi 81 82 # We must check for the threads library under a number of different 83 # names; the ordering is very important because some systems 84 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the 85 # libraries is broken (non-POSIX). 86 87 # Create a list of thread flags to try. Items starting with a "-" are 88 # C compiler flags, and other items are library names, except for "none" 89 # which indicates that we try without any flags at all, and "pthread-config" 90 # which is a program returning the flags for the Pth emulation library. 91 92 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" 93 94 # The ordering *is* (sometimes) important. Some notes on the 95 # individual items follow: 96 97 # pthreads: AIX (must check this before -lpthread) 98 # none: in case threads are in libc; should be tried before -Kthread and 99 # other compiler flags to prevent continual compiler warnings 100 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) 101 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) 102 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) 103 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads) 104 # -pthreads: Solaris/gcc 105 # -mthreads: Mingw32/gcc, Lynx/gcc 106 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it 107 # doesn't hurt to check since this sometimes defines pthreads too; 108 # also defines -D_REENTRANT) 109 # ... -mt is also the pthreads flag for HP/aCC 110 # pthread: Linux, etcetera 111 # --thread-safe: KAI C++ 112 # pthread-config: use pthread-config program (for GNU Pth library) 113 114 case "${host_cpu}-${host_os}" in 115 *solaris*) 116 117 # On Solaris (at least, for some versions), libc contains stubbed 118 # (non-functional) versions of the pthreads routines, so link-based 119 # tests will erroneously succeed. (We need to link with -pthreads/-mt/ 120 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather 121 # a function called by this macro, so we could check for that, but 122 # who knows whether they'll stub that too in a future libc.) So, 123 # we'll just look for -pthreads and -lpthread first: 124 125 acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags" 126 ;; 127 esac 128 129 if test x"$acx_pthread_ok" = xno; then 130 for flag in $acx_pthread_flags; do 131 132 case $flag in 133 none) 134 AC_MSG_CHECKING([whether pthreads work without any flags]) 135 ;; 136 137 -*) 138 AC_MSG_CHECKING([whether pthreads work with $flag]) 139 PTHREAD_CFLAGS="$flag" 140 ;; 141 142 pthread-config) 143 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no) 144 if test x"$acx_pthread_config" = xno; then continue; fi 145 PTHREAD_CFLAGS="`pthread-config --cflags`" 146 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" 147 ;; 148 149 *) 150 AC_MSG_CHECKING([for the pthreads library -l$flag]) 151 PTHREAD_LIBS="-l$flag" 152 ;; 153 esac 154 155 save_LIBS="$LIBS" 156 save_CFLAGS="$CFLAGS" 157 LIBS="$PTHREAD_LIBS $LIBS" 158 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 159 160 # Check for various functions. We must include pthread.h, 161 # since some functions may be macros. (On the Sequent, we 162 # need a special flag -Kthread to make this header compile.) 163 # We check for pthread_join because it is in -lpthread on IRIX 164 # while pthread_create is in libc. We check for pthread_attr_init 165 # due to DEC craziness with -lpthreads. We check for 166 # pthread_cleanup_push because it is one of the few pthread 167 # functions on Solaris that doesn't have a non-functional libc stub. 168 # We try pthread_create on general principles. 169 AC_TRY_LINK([#include <pthread.h>], 170 [pthread_t th; pthread_join(th, 0); 171 pthread_attr_init(0); pthread_cleanup_push(0, 0); 172 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 173 [acx_pthread_ok=yes]) 174 175 LIBS="$save_LIBS" 176 CFLAGS="$save_CFLAGS" 177 178 AC_MSG_RESULT($acx_pthread_ok) 179 if test "x$acx_pthread_ok" = xyes; then 180 break; 181 fi 182 183 PTHREAD_LIBS="" 184 PTHREAD_CFLAGS="" 185 done 186 fi 187 188 # Various other checks: 189 if test "x$acx_pthread_ok" = xyes; then 190 save_LIBS="$LIBS" 191 LIBS="$PTHREAD_LIBS $LIBS" 192 save_CFLAGS="$CFLAGS" 193 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 194 195 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. 196 AC_MSG_CHECKING([for joinable pthread attribute]) 197 attr_name=unknown 198 for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do 199 AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;], 200 [attr_name=$attr; break]) 201 done 202 AC_MSG_RESULT($attr_name) 203 if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then 204 AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name, 205 [Define to necessary symbol if this constant 206 uses a non-standard name on your system.]) 207 fi 208 209 AC_MSG_CHECKING([if more special flags are required for pthreads]) 210 flag=no 211 case "${host_cpu}-${host_os}" in 212 *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";; 213 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";; 214 esac 215 AC_MSG_RESULT(${flag}) 216 if test "x$flag" != xno; then 217 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS" 218 fi 219 220 LIBS="$save_LIBS" 221 CFLAGS="$save_CFLAGS" 222 # More AIX lossage: must compile with xlc_r or cc_r 223 if test x"$GCC" != xyes; then 224 AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC}) 225 else 226 PTHREAD_CC=$CC 227 fi 228 229 # The next part tries to detect GCC inconsistency with -shared on some 230 # architectures and systems. The problem is that in certain 231 # configurations, when -shared is specified, GCC "forgets" to 232 # internally use various flags which are still necessary. 233 234 AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies]) 235 check_inconsistencies=yes 236 case "${host_cpu}-${host_os}" in 237 *-darwin* | *-androideabi ) check_inconsistencies=no ;; 238 esac 239 if test x"$GCC" != xyes -o "x$check_inconsistencies" != xyes ; then 240 AC_MSG_RESULT([no]) 241 else 242 AC_MSG_RESULT([yes]) 243 244 # In order not to create several levels of indentation, we test 245 # the value of "$ok" until we find out the cure or run out of 246 # ideas. 247 ok="no" 248 249 # 250 # Prepare the flags 251 # 252 save_CFLAGS="$CFLAGS" 253 save_LIBS="$LIBS" 254 save_CC="$CC" 255 # Try with the flags determined by the earlier checks. 256 # 257 # -Wl,-z,defs forces link-time symbol resolution, so that the 258 # linking checks with -shared actually have any value 259 # 260 # FIXME: -fPIC is required for -shared on many architectures, 261 # so we specify it here, but the right way would probably be to 262 # properly detect whether it is actually required. 263 CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS" 264 LIBS="$PTHREAD_LIBS $LIBS" 265 CC="$PTHREAD_CC" 266 267 AC_MSG_CHECKING([whether -pthread is sufficient with -shared]) 268 AC_TRY_LINK([#include <pthread.h>], 269 [pthread_t th; pthread_join(th, 0); 270 pthread_attr_init(0); pthread_cleanup_push(0, 0); 271 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 272 [ok=yes]) 273 274 if test "x$ok" = xyes; then 275 AC_MSG_RESULT([yes]) 276 else 277 AC_MSG_RESULT([no]) 278 fi 279 280 # 281 # Linux gcc on some architectures such as mips/mipsel forgets 282 # about -lpthread 283 # 284 if test x"$ok" = xno; then 285 AC_MSG_CHECKING([whether -lpthread fixes that]) 286 LIBS="-lpthread $PTHREAD_LIBS $save_LIBS" 287 AC_TRY_LINK([#include <pthread.h>], 288 [pthread_t th; pthread_join(th, 0); 289 pthread_attr_init(0); pthread_cleanup_push(0, 0); 290 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 291 [ok=yes]) 292 293 if test "x$ok" = xyes; then 294 AC_MSG_RESULT([yes]) 295 PTHREAD_LIBS="-lpthread $PTHREAD_LIBS" 296 else 297 AC_MSG_RESULT([no]) 298 fi 299 fi 300 # 301 # FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc 302 # 303 if test x"$ok" = xno; then 304 AC_MSG_CHECKING([whether -lc_r fixes that]) 305 LIBS="-lc_r $PTHREAD_LIBS $save_LIBS" 306 AC_TRY_LINK([#include <pthread.h>], 307 [pthread_t th; pthread_join(th, 0); 308 pthread_attr_init(0); pthread_cleanup_push(0, 0); 309 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 310 [ok=yes]) 311 312 if test "x$ok" = xyes; then 313 AC_MSG_RESULT([yes]) 314 PTHREAD_LIBS="-lc_r $PTHREAD_LIBS" 315 else 316 AC_MSG_RESULT([no]) 317 fi 318 fi 319 if test x"$ok" = xno; then 320 # OK, we have run out of ideas 321 AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries]) 322 323 # so it's not safe to assume that we may use pthreads 324 acx_pthread_ok=no 325 fi 326 327 CFLAGS="$save_CFLAGS" 328 LIBS="$save_LIBS" 329 CC="$save_CC" 330 fi 331 else 332 PTHREAD_CC="$CC" 333 fi 334 335 AC_SUBST(PTHREAD_LIBS) 336 AC_SUBST(PTHREAD_CFLAGS) 337 AC_SUBST(PTHREAD_CC) 338 339 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: 340 if test x"$acx_pthread_ok" = xyes; then 341 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1]) 342 : 343 else 344 acx_pthread_ok=no 345 $2 346 fi 347 AC_LANG_RESTORE 348 ])dnl ACX_PTHREAD 349
