diff options
Diffstat (limited to 'common/acx_pthread.m4')
| -rw-r--r-- | common/acx_pthread.m4 | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/common/acx_pthread.m4 b/common/acx_pthread.m4 index 06af842..a96d31d 100644 --- a/common/acx_pthread.m4 +++ b/common/acx_pthread.m4 @@ -45,6 +45,10 @@ dnl @category InstalledPackages dnl @author Steven G. Johnson <stevenj@alum.mit.edu> dnl @version 2005-06-15 dnl @license GPLWithACException +dnl +dnl Checks for GCC shared/pthread inconsistency based on work by +dnl Marcin Owsiany <marcin@owsiany.pl> + AC_DEFUN([ACX_PTHREAD], [ AC_REQUIRE([AC_CANONICAL_HOST]) @@ -218,6 +222,107 @@ if test "x$acx_pthread_ok" = xyes; then # More AIX lossage: must compile with cc_r AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC}) + + # The next part tries to detect GCC inconsistency with -shared on some + # architectures and systems. The problem is that in certain + # configurations, when -shared is specified, GCC "forgets" to + # internally use various flags which are still necessary. + + # First, check whether caller wants us to skip -shared checks + # this is useful + AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies]) + if test x"$3" = x1; then + AC_MSG_RESULT([no]) + else + AC_MSG_RESULT([yes]) + + # In order not to create several levels of indentation, we test + # the value of "$ok" until we find out the cure or run out of + # ideas. + ok="no" + + # + # Prepare the flags + # + save_CFLAGS="$CFLAGS" + save_LIBS="$LIBS" + save_CC="$CC" + # Try with the flags determined by the earlier checks. + # + # -Wl,-z,defs forces link-time symbol resolution, so that the + # linking checks with -shared actually have any value + # + # FIXME: -fPIC is required for -shared on many architectures, + # so we specify it here, but the right way would probably be to + # properly detect whether it is actually required. + CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS" + LIBS="$PTHREAD_LIBS $LIBS" + CC="$PTHREAD_CC" + + AC_MSG_CHECKING([whether -pthread is sufficient with -shared]) + AC_TRY_LINK([#include <pthread.h>], + [pthread_t th; pthread_join(th, 0); + pthread_attr_init(0); pthread_cleanup_push(0, 0); + pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], + [ok=yes]) + + if test "x$ok" = xyes; then + AC_MSG_RESULT([yes]) + else + AC_MSG_RESULT([no]) + fi + + # + # Linux gcc on some architectures such as mips/mipsel forgets + # about -lpthread + # + if test x"$ok" = xno; then + AC_MSG_CHECKING([whether -lpthread fixes that]) + LIBS="-lpthread $PTHREAD_LIBS $save_LIBS" + AC_TRY_LINK([#include <pthread.h>], + [pthread_t th; pthread_join(th, 0); + pthread_attr_init(0); pthread_cleanup_push(0, 0); + pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], + [ok=yes]) + + if test "x$ok" = xyes; then + AC_MSG_RESULT([yes]) + PTHREAD_LIBS="-lpthread $PTHREAD_LIBS" + else + AC_MSG_RESULT([no]) + fi + fi + # + # FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc + # + if test x"$ok" = xno; then + AC_MSG_CHECKING([whether -lc_r fixes that]) + LIBS="-lc_r $PTHREAD_LIBS $save_LIBS" + AC_TRY_LINK([#include <pthread.h>], + [pthread_t th; pthread_join(th, 0); + pthread_attr_init(0); pthread_cleanup_push(0, 0); + pthread_create(0,0,0,0); pthread_cleanup_pop(0); ], + [ok=yes]) + + if test "x$ok" = xyes; then + AC_MSG_RESULT([yes]) + PTHREAD_LIBS="-lc_r $PTHREAD_LIBS" + else + AC_MSG_RESULT([no]) + fi + fi + if test x"$ok" = xno; then + # OK, we have run out of ideas + AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries]) + + # so it's not safe to assume that we may use pthreads + acx_pthread_ok=no + fi + + CFLAGS="$save_CFLAGS" + LIBS="$save_LIBS" + CC="$save_CC" + fi else PTHREAD_CC="$CC" fi |