1dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]]) 2dnl 3dnl @summary figure out how to build C programs using POSIX threads 4dnl 5dnl This macro figures out how to build C programs using POSIX threads. 6dnl It sets the PTHREAD_LIBS output variable to the threads library and 7dnl linker flags, and the PTHREAD_CFLAGS output variable to any special 8dnl C compiler flags that are needed. (The user can also force certain 9dnl compiler flags/libs to be tested by setting these environment 10dnl variables.) 11dnl 12dnl Also sets PTHREAD_CC to any special C compiler that is needed for 13dnl multi-threaded programs (defaults to the value of CC otherwise). 14dnl (This is necessary on AIX to use the special cc_r compiler alias.) 15dnl 16dnl NOTE: You are assumed to not only compile your program with these 17dnl flags, but also link it with them as well. e.g. you should link 18dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS 19dnl $LIBS 20dnl 21dnl If you are only building threads programs, you may wish to use 22dnl these variables in your default LIBS, CFLAGS, and CC: 23dnl 24dnl LIBS="$PTHREAD_LIBS $LIBS" 25dnl CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 26dnl CC="$PTHREAD_CC" 27dnl 28dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute 29dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to 30dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX). 31dnl 32dnl ACTION-IF-FOUND is a list of shell commands to run if a threads 33dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to 34dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the 35dnl default action will define HAVE_PTHREAD. 36dnl 37dnl Please let the authors know if this macro fails on any platform, or 38dnl if you have any other suggestions or comments. This macro was based 39dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with 40dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros 41dnl posted by Alejandro Forero Cuervo to the autoconf macro repository. 42dnl We are also grateful for the helpful feedback of numerous users. 43dnl 44dnl @category InstalledPackages 45dnl @author Steven G. Johnson <stevenj@alum.mit.edu> 46dnl @version 2006-05-29 47dnl @license GPLWithACException 48 49AC_DEFUN([ACX_PTHREAD], [ 50AC_REQUIRE([AC_CANONICAL_HOST]) 51AC_LANG_SAVE 52AC_LANG_C 53acx_pthread_ok=no 54 55# We used to check for pthread.h first, but this fails if pthread.h 56# requires special compiler flags (e.g. on True64 or Sequent). 57# It gets checked for in the link test anyway. 58 59# First of all, check if the user has set any of the PTHREAD_LIBS, 60# etcetera environment variables, and if threads linking works using 61# them: 62if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then 63 save_CFLAGS="$CFLAGS" 64 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 65 save_LIBS="$LIBS" 66 LIBS="$PTHREAD_LIBS $LIBS" 67 AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS]) 68 AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes) 69 AC_MSG_RESULT($acx_pthread_ok) 70 if test x"$acx_pthread_ok" = xno; then 71 PTHREAD_LIBS="" 72 PTHREAD_CFLAGS="" 73 fi 74 LIBS="$save_LIBS" 75 CFLAGS="$save_CFLAGS" 76fi 77 78# We must check for the threads library under a number of different 79# names; the ordering is very important because some systems 80# (e.g. DEC) have both -lpthread and -lpthreads, where one of the 81# libraries is broken (non-POSIX). 82 83# Create a list of thread flags to try. Items starting with a "-" are 84# C compiler flags, and other items are library names, except for "none" 85# which indicates that we try without any flags at all, and "pthread-config" 86# which is a program returning the flags for the Pth emulation library. 87 88acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config" 89 90# The ordering *is* (sometimes) important. Some notes on the 91# individual items follow: 92 93# pthreads: AIX (must check this before -lpthread) 94# none: in case threads are in libc; should be tried before -Kthread and 95# other compiler flags to prevent continual compiler warnings 96# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h) 97# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able) 98# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread) 99# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads) 100# -pthreads: Solaris/gcc 101# -mthreads: Mingw32/gcc, Lynx/gcc 102# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it 103# doesn't hurt to check since this sometimes defines pthreads too; 104# also defines -D_REENTRANT) 105# ... -mt is also the pthreads flag for HP/aCC 106# pthread: Linux, etcetera 107# --thread-safe: KAI C++ 108# pthread-config: use pthread-config program (for GNU Pth library) 109 110case "${host_cpu}-${host_os}" in 111 *solaris*) 112 113 # On Solaris (at least, for some versions), libc contains stubbed 114 # (non-functional) versions of the pthreads routines, so link-based 115 # tests will erroneously succeed. (We need to link with -pthreads/-mt/ 116 # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather 117 # a function called by this macro, so we could check for that, but 118 # who knows whether they'll stub that too in a future libc.) So, 119 # we'll just look for -pthreads and -lpthread first: 120 121 acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags" 122 ;; 123esac 124 125if test x"$acx_pthread_ok" = xno; then 126for flag in $acx_pthread_flags; do 127 128 case $flag in 129 none) 130 AC_MSG_CHECKING([whether pthreads work without any flags]) 131 ;; 132 133 -*) 134 AC_MSG_CHECKING([whether pthreads work with $flag]) 135 PTHREAD_CFLAGS="$flag" 136 ;; 137 138 pthread-config) 139 AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no) 140 if test x"$acx_pthread_config" = xno; then continue; fi 141 PTHREAD_CFLAGS="`pthread-config --cflags`" 142 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`" 143 ;; 144 145 *) 146 AC_MSG_CHECKING([for the pthreads library -l$flag]) 147 PTHREAD_LIBS="-l$flag" 148 ;; 149 esac 150 151 save_LIBS="$LIBS" 152 save_CFLAGS="$CFLAGS" 153 LIBS="$PTHREAD_LIBS $LIBS" 154 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 155 156 # Check for various functions. We must include pthread.h, 157 # since some functions may be macros. (On the Sequent, we 158 # need a special flag -Kthread to make this header compile.) 159 # We check for pthread_join because it is in -lpthread on IRIX 160 # while pthread_create is in libc. We check for pthread_attr_init 161 # due to DEC craziness with -lpthreads. We check for 162 # pthread_cleanup_push because it is one of the few pthread 163 # functions on Solaris that doesn't have a non-functional libc stub. 164 # We try pthread_create on general principles. 165 AC_TRY_LINK([#include <pthread.h>], 166 [pthread_t th; pthread_join(th, 0); 167 pthread_attr_init(0); pthread_cleanup_push(0, 0); 168 pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], 169 [acx_pthread_ok=yes]) 170 171 LIBS="$save_LIBS" 172 CFLAGS="$save_CFLAGS" 173 174 AC_MSG_RESULT($acx_pthread_ok) 175 if test "x$acx_pthread_ok" = xyes; then 176 break; 177 fi 178 179 PTHREAD_LIBS="" 180 PTHREAD_CFLAGS="" 181done 182fi 183 184# Various other checks: 185if test "x$acx_pthread_ok" = xyes; then 186 save_LIBS="$LIBS" 187 LIBS="$PTHREAD_LIBS $LIBS" 188 save_CFLAGS="$CFLAGS" 189 CFLAGS="$CFLAGS $PTHREAD_CFLAGS" 190 191 # Detect AIX lossage: JOINABLE attribute is called UNDETACHED. 192 AC_MSG_CHECKING([for joinable pthread attribute]) 193 attr_name=unknown 194 for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do 195 AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;], 196 [attr_name=$attr; break]) 197 done 198 AC_MSG_RESULT($attr_name) 199 if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then 200 AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name, 201 [Define to necessary symbol if this constant 202 uses a non-standard name on your system.]) 203 fi 204 205 AC_MSG_CHECKING([if more special flags are required for pthreads]) 206 flag=no 207 case "${host_cpu}-${host_os}" in 208 *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";; 209 *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";; 210 esac 211 AC_MSG_RESULT(${flag}) 212 if test "x$flag" != xno; then 213 PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS" 214 fi 215 216 LIBS="$save_LIBS" 217 CFLAGS="$save_CFLAGS" 218 219 # More AIX lossage: must compile with xlc_r or cc_r 220 if test x"$GCC" != xyes; then 221 AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC}) 222 else 223 PTHREAD_CC=$CC 224 fi 225else 226 PTHREAD_CC="$CC" 227fi 228 229AC_SUBST(PTHREAD_LIBS) 230AC_SUBST(PTHREAD_CFLAGS) 231AC_SUBST(PTHREAD_CC) 232 233# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND: 234if test x"$acx_pthread_ok" = xyes; then 235 ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1]) 236 : 237else 238 acx_pthread_ok=no 239 $2 240fi 241AC_LANG_RESTORE 242])dnl ACX_PTHREAD 243