ObjFW  Diff

		yes
		#endif
		], [
		AC_MSG_RESULT(yes)
		atomic_ops="assembly implementation"
		], [AC_MSG_RESULT(no)])

	if test x"$atomic_ops" = x"none"; then
		AC_MSG_CHECKING(whether __sync_* works)
		AC_TRY_LINK([#include <stdint.h>], [
			int32_t i, j;
			if (__sync_add_and_fetch(&i, 1))
				j = __sync_sub_and_fetch(&i, 1);
			while (!__sync_bool_compare_and_swap(&i, 0, 1));
			], [
			AC_MSG_RESULT(yes)
			atomic_ops="gcc builtins"
			AC_DEFINE(OF_HAVE_GCC_ATOMIC_OPS, 1,
				[Whether gcc atomic operations are available])
			], [AC_MSG_RESULT(no)])
	AC_MSG_CHECKING(whether __sync_* works)
	AC_TRY_LINK([#include <stdint.h>], [
		int32_t i, j;
		if (__sync_add_and_fetch(&i, 1))
			j = __sync_sub_and_fetch(&i, 1);
		while (!__sync_bool_compare_and_swap(&i, 0, 1));
		], [
		AC_MSG_RESULT(yes)
		test x"$atomic_ops" = x"none" && atomic_ops="gcc builtins"
		AC_DEFINE(OF_HAVE_GCC_ATOMIC_OPS, 1,
			[Whether gcc atomic operations are available])
		], [AC_MSG_RESULT(no)])
	fi

	if test x"$atomic_ops" = x"none"; then
		AC_CHECK_HEADER(libkern/OSAtomic.h, [
			atomic_ops="libkern/OSAtomic.h"
			AC_DEFINE(OF_HAVE_LIBKERN_OSATOMIC_H, 1,
				[Whether we have libkern/OSAtomic.h])])
	AC_CHECK_HEADER(libkern/OSAtomic.h, [
		test x"$atomic_ops" = x"none" && atomic_ops="libkern/OSAtomic.h"
		AC_DEFINE(OF_HAVE_LIBKERN_OSATOMIC_H, 1,
			[Whether we have libkern/OSAtomic.h])])
	fi
else
	dnl We can only have one thread - therefore everything is atomic
	atomic_ops="not needed"
fi

AC_MSG_CHECKING(for atomic operations)
if test x"$atomic_ops" != x"none"; then