1 # This was retrieved from 2 # http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?revision=1277&root=avahi 3 # See also (perhaps for new versions?) 4 # http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?root=avahi 5 # 6 # We've rewritten the inconsistency check code (from avahi), to work 7 # more broadly. In particular, it no longer assumes ld accepts -zdefs. 8 # This caused a restructing of the code, but the functionality has only 9 # changed a little. 10 11 dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 12 dnl 13 dnl @summary figure out how to build C programs using POSIX threads 14 dnl 15 dnl This macro figures out how to build C programs using POSIX threads. 16 dnl It sets the PTHREAD_LIBS output variable to the threads library and 17 dnl linker flags, and the PTHREAD_CFLAGS output variable to any special 18 dnl C compiler flags that are needed. (The user can also force certain 19 dnl compiler flags/libs to be tested by setting these environment 20 dnl variables.) 21 dnl 22 dnl Also sets PTHREAD_CC to any special C compiler that is needed for 23 dnl multi-threaded programs (defaults to the value of CC otherwise). 24 dnl (This is necessary on AIX to use the special cc_r compiler alias.) 25 dnl 26 dnl NOTE: You are assumed to not only compile your program with these 27 dnl flags, but also link it with them as well. e.g. you should link 28 dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS 29 dnl $LIBS 30 dnl 31 dnl If you are only building threads programs, you may wish to use 32 dnl these variables in your default LIBS, CFLAGS, and CC: 33 dnl 34 dnl LIBS="$PTHREAD_LIBS $LIBS" 35 dnl CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 36 dnl CC="$PTHREAD_CC" 37 dnl 38 dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute 39 dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to 40 dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). 41 dnl 42 dnl ACTION-IF-FOUND is a list of shell commands to run if a threads 43 dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to 44 dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the 45 dnl default action will define HAVE_PTHREAD. 46 dnl 47 dnl Please let the authors know if this macro fails on any platform, or 48 dnl if you have any other suggestions or comments. This macro was based 49 dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with 50 dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros 51 dnl posted by Alejandro Forero Cuervo to the autoconf macro repository. 52 dnl We are also grateful for the helpful feedback of numerous users. 53 dnl 54 dnl @category InstalledPackages 55 dnl @author Steven G. Johnson <stevenj (a] alum.mit.edu> 56 dnl @version 2006-05-29 57 dnl @license GPLWithACException 58 dnl 59 dnl Checks for GCC shared/pthread inconsistency based on work by 60 dnl Marcin Owsiany <marcin (a] owsiany.pl> 61 62 63 AC_DEFUN([ACX_PTHREAD], [ 64 AC_REQUIRE([AC_CANONICAL_HOST]) 65 AC_LANG_SAVE 66 AC_LANG_C 67 acx_pthread_ok=no 68 69 # We used to check for pthread.h first, but this fails if pthread.h 70 # requires special compiler flags (e.g. on True64 or Sequent). 71 # It gets checked for in the link test anyway. 72 73 # First of all, check if the user has set any of the PTHREAD_LIBS, 74 # etcetera environment variables, and if threads linking works using 75 # them: 76 if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then 77 save_CFLAGS="$CFLAGS" 78 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 79 save_LIBS="$LIBS" 80 LIBS="$PTHREAD_LIBS $LIBS" 81 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS]) 82 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes) 83 AC_MSG_RESULT($acx_pthread_ok) 84 if test x"$acx_pthread_ok" = xno; then 85 PTHREAD_LIBS="" 86 PTHREAD_CFLAGS="" 87 fi 88 LIBS="$save_LIBS" 89 CFLAGS="$save_CFLAGS" 90 fi 91 92 # We must check for the threads library under a number of different 93 # names; the ordering is very important because some systems 94 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the 95 # libraries is broken (non-POSIX). 96 97 # Create a list of thread flags to try. Items starting with a "-" are 98 # C compiler flags, and other items are library names, except for "none" 99 # which indicates that we try without any flags at all, and "pthread-config" 100 # which is a program returning the flags for the Pth emulation library. 101 102 acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" 103 104 # The ordering *is* (sometimes) important. Some notes on the 105 # individual items follow: 106 107 # pthreads: AIX (must check this before -lpthread) 108 # none: in case threads are in libc; should be tried before -Kthread and 109 # other compiler flags to prevent continual compiler warnings 110 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) 111 # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) 112 # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) 113 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads) 114 # -pthreads: Solaris/gcc 115 # -mthreads: Mingw32/gcc, Lynx/gcc 116 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it 117 # doesn't hurt to check since this sometimes defines pthreads too; 118 # also defines -D_REENTRANT) 119 # ... -mt is also the pthreads flag for HP/aCC 120 # pthread: Linux, etcetera 121 # --thread-safe: KAI C++ 122 # pthread-config: use pthread-config program (for GNU Pth library) 123 124 case "${host_cpu}-${host_os}" in 125 *solaris*) 126 127 # On Solaris (at least, for some versions), libc contains stubbed 128 # (non-functional) versions of the pthreads routines, so link-based 129 # tests will erroneously succeed. (We need to link with -pthreads/-mt/ 130 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather 131 # a function called by this macro, so we could check for that, but 132 # who knows whether they'll stub that too in a future libc.) So, 133 # we'll just look for -pthreads and -lpthread first: 134 135 acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags" 136 ;; 137 esac 138 139 if test x"$acx_pthread_ok" = xno; then 140 for flag in $acx_pthread_flags; do 141 142 case $flag in 143 none) 144 AC_MSG_CHECKING([whether pthreads work without any flags]) 145 ;; 146 147 -*) 148 AC_MSG_CHECKING([whether pthreads work with $flag]) 149 PTHREAD_CFLAGS="$flag" 150 ;; 151 152 pthread-config) 153 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no) 154 if test x"$acx_pthread_config" = xno; then continue; fi 155 PTHREAD_CFLAGS="`pthread-config --cflags`" 156 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" 157 ;; 158 159 *) 160 AC_MSG_CHECKING([for the pthreads library -l$flag]) 161 PTHREAD_LIBS="-l$flag" 162 ;; 163 esac 164 165 save_LIBS="$LIBS" 166 save_CFLAGS="$CFLAGS" 167 LIBS="$PTHREAD_LIBS $LIBS" 168 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 169 170 # Check for various functions. We must include pthread.h, 171 # since some functions may be macros. (On the Sequent, we 172 # need a special flag -Kthread to make this header compile.) 173 # We check for pthread_join because it is in -lpthread on IRIX 174 # while pthread_create is in libc. We check for pthread_attr_init 175 # due to DEC craziness with -lpthreads. We check for 176 # pthread_cleanup_push because it is one of the few pthread 177 # functions on Solaris that doesn't have a non-functional libc stub. 178 # We try pthread_create on general principles. 179 AC_TRY_LINK([#include <pthread.h>], 180 [pthread_t th; pthread_join(th, 0); 181 pthread_attr_init(0); pthread_cleanup_push(0, 0); 182 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 183 [acx_pthread_ok=yes]) 184 185 LIBS="$save_LIBS" 186 CFLAGS="$save_CFLAGS" 187 188 AC_MSG_RESULT($acx_pthread_ok) 189 if test "x$acx_pthread_ok" = xyes; then 190 break; 191 fi 192 193 PTHREAD_LIBS="" 194 PTHREAD_CFLAGS="" 195 done 196 fi 197 198 # Various other checks: 199 if test "x$acx_pthread_ok" = xyes; then 200 save_LIBS="$LIBS" 201 LIBS="$PTHREAD_LIBS $LIBS" 202 save_CFLAGS="$CFLAGS" 203 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 204 205 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. 206 AC_MSG_CHECKING([for joinable pthread attribute]) 207 attr_name=unknown 208 for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do 209 AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;], 210 [attr_name=$attr; break]) 211 done 212 AC_MSG_RESULT($attr_name) 213 if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then 214 AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name, 215 [Define to necessary symbol if this constant 216 uses a non-standard name on your system.]) 217 fi 218 219 AC_MSG_CHECKING([if more special flags are required for pthreads]) 220 flag=no 221 case "${host_cpu}-${host_os}" in 222 *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";; 223 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";; 224 esac 225 AC_MSG_RESULT(${flag}) 226 if test "x$flag" != xno; then 227 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS" 228 fi 229 230 LIBS="$save_LIBS" 231 CFLAGS="$save_CFLAGS" 232 # More AIX lossage: must compile with xlc_r or cc_r 233 if test x"$GCC" != xyes; then 234 AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC}) 235 else 236 PTHREAD_CC=$CC 237 fi 238 239 # The next part tries to detect GCC inconsistency with -shared on some 240 # architectures and systems. The problem is that in certain 241 # configurations, when -shared is specified, GCC "forgets" to 242 # internally use various flags which are still necessary. 243 244 # 245 # Prepare the flags 246 # 247 save_CFLAGS="$CFLAGS" 248 save_LIBS="$LIBS" 249 save_CC="$CC" 250 251 # Try with the flags determined by the earlier checks. 252 # 253 # -Wl,-z,defs forces link-time symbol resolution, so that the 254 # linking checks with -shared actually have any value 255 # 256 # FIXME: -fPIC is required for -shared on many architectures, 257 # so we specify it here, but the right way would probably be to 258 # properly detect whether it is actually required. 259 CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS" 260 LIBS="$PTHREAD_LIBS $LIBS" 261 CC="$PTHREAD_CC" 262 263 # In order not to create several levels of indentation, we test 264 # the value of "$done" until we find the cure or run out of ideas. 265 done="no" 266 267 # First, make sure the CFLAGS we added are actually accepted by our 268 # compiler. If not (and OS X's ld, for instance, does not accept -z), 269 # then we can't do this test. 270 if test x"$done" = xno; then 271 AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies]) 272 AC_TRY_LINK(,, , [done=yes]) 273 274 if test "x$done" = xyes ; then 275 AC_MSG_RESULT([no]) 276 else 277 AC_MSG_RESULT([yes]) 278 fi 279 fi 280 281 if test x"$done" = xno; then 282 AC_MSG_CHECKING([whether -pthread is sufficient with -shared]) 283 AC_TRY_LINK([#include <pthread.h>], 284 [pthread_t th; pthread_join(th, 0); 285 pthread_attr_init(0); pthread_cleanup_push(0, 0); 286 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 287 [done=yes]) 288 289 if test "x$done" = xyes; then 290 AC_MSG_RESULT([yes]) 291 else 292 AC_MSG_RESULT([no]) 293 fi 294 fi 295 296 # 297 # Linux gcc on some architectures such as mips/mipsel forgets 298 # about -lpthread 299 # 300 if test x"$done" = xno; then 301 AC_MSG_CHECKING([whether -lpthread fixes that]) 302 LIBS="-lpthread $PTHREAD_LIBS $save_LIBS" 303 AC_TRY_LINK([#include <pthread.h>], 304 [pthread_t th; pthread_join(th, 0); 305 pthread_attr_init(0); pthread_cleanup_push(0, 0); 306 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 307 [done=yes]) 308 309 if test "x$done" = xyes; then 310 AC_MSG_RESULT([yes]) 311 PTHREAD_LIBS="-lpthread $PTHREAD_LIBS" 312 else 313 AC_MSG_RESULT([no]) 314 fi 315 fi 316 # 317 # FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc 318 # 319 if test x"$done" = xno; then 320 AC_MSG_CHECKING([whether -lc_r fixes that]) 321 LIBS="-lc_r $PTHREAD_LIBS $save_LIBS" 322 AC_TRY_LINK([#include <pthread.h>], 323 [pthread_t th; pthread_join(th, 0); 324 pthread_attr_init(0); pthread_cleanup_push(0, 0); 325 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 326 [done=yes]) 327 328 if test "x$done" = xyes; then 329 AC_MSG_RESULT([yes]) 330 PTHREAD_LIBS="-lc_r $PTHREAD_LIBS" 331 else 332 AC_MSG_RESULT([no]) 333 fi 334 fi 335 if test x"$done" = xno; then 336 # OK, we have run out of ideas 337 AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries]) 338 339 # so it's not safe to assume that we may use pthreads 340 acx_pthread_ok=no 341 fi 342 343 CFLAGS="$save_CFLAGS" 344 LIBS="$save_LIBS" 345 CC="$save_CC" 346 else 347 PTHREAD_CC="$CC" 348 fi 349 350 AC_SUBST(PTHREAD_LIBS) 351 AC_SUBST(PTHREAD_CFLAGS) 352 AC_SUBST(PTHREAD_CC) 353 354 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: 355 if test x"$acx_pthread_ok" = xyes; then 356 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1]) 357 : 358 else 359 acx_pthread_ok=no 360 $2 361 fi 362 AC_LANG_RESTORE 363 ])dnl ACX_PTHREAD 364
