diff options
Diffstat (limited to 'm4/ax_c___atomic.m4')
| -rw-r--r-- | m4/ax_c___atomic.m4 | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/m4/ax_c___atomic.m4 b/m4/ax_c___atomic.m4 new file mode 100644 index 000000000..131929ae1 --- /dev/null +++ b/m4/ax_c___atomic.m4 @@ -0,0 +1,30 @@ +# AC_C___ATOMIC +# ------------- +# Define HAVE_C___ATOMIC if __atomic works. +AN_IDENTIFIER([__atomic], [AC_C___ATOMIC]) +AC_DEFUN([AC_C___ATOMIC], +[AC_CACHE_CHECK([for __atomic], ac_cv_c___atomic, +[AC_LINK_IFELSE( + [AC_LANG_SOURCE( + [[int + main (int argc, char **argv) + { + volatile unsigned long ul1 = 1, ul2 = 0, ul3 = 2; + __atomic_compare_exchange(&ul1, &ul2, &ul3, 1, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); + __atomic_fetch_add(&ul1, 1, __ATOMIC_SEQ_CST); + __atomic_fetch_sub(&ul3, 1, __ATOMIC_SEQ_CST); + volatile unsigned long long ull1 = 1, ull2 = 0, ull3 = 2; + __atomic_compare_exchange(&ull1, &ull2, &ull3, 1, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); + __atomic_fetch_add(&ull1, 1, __ATOMIC_SEQ_CST); + __atomic_fetch_sub(&ull3, 1, __ATOMIC_SEQ_CST); + return 0; + } + ]])], + [ac_cv_c___atomic=yes], + [ac_cv_c___atomic=no])]) +if test $ac_cv_c___atomic = yes; then + AC_DEFINE([HAVE_C___ATOMIC], 1, + [Define to 1 if __atomic operations work.]) +fi +])# AC_C___ATOMIC + |