improve __sync_sub_and_fetch detection MapServer#4231

faegi · Dec 12, 2012 · c3552d7 · c3552d7
1 parent 546223d
commit c3552d7
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/configure b/configure
@@ -17836,7 +17836,7 @@ else
 int
 main ()
 {
-long x;long y=__sync_fetch_and_add(&x,1);
+long x=0,y=0;for(x=0;x<5;x++){if(y>1) break; y=__sync_fetch_and_add(&x,1);}
   ;
   return 0;
 }

diff --git a/configure.in b/configure.in
@@ -851,7 +851,7 @@ dnl ---------------------------------------------------------------------
 dnl Check for the __sync_fetch_and_add builtin
 dnl ---------------------------------------------------------------------
 AC_CACHE_CHECK([for __sync_fetch_and_add], ac_cv_func_sync_fetch_and_add,
-[AC_TRY_LINK([],[long x;long y=__sync_fetch_and_add(&x,1);],ac_cv_func_sync_fetch_and_add=yes,ac_cv_func_sync_fetch_and_add=no)])
+[AC_TRY_LINK([],[long x=0,y=0;for(x=0;x<5;x++){if(y>1) break; y=__sync_fetch_and_add(&x,1);}],ac_cv_func_sync_fetch_and_add=yes,ac_cv_func_sync_fetch_and_add=no)])
 if test "$ac_cv_func_sync_fetch_and_add" = yes; then
   ALL_ENABLED="-DHAVE_SYNC_FETCH_AND_ADD $ALL_ENABLED"
   AC_DEFINE(HAVE_SYNC_FETCH_AND_ADD,1,[Define if you have the __sync_fetch_and_add function])