sync_with_child
FAIL_IF(sync_with_child(read_pipe, write_pipe));
if (sync_with_child(read_pipe, write_pipe))
FAIL_IF(sync_with_child(read_pipe, write_pipe));
if (sync_with_child(read_pipe, write_pipe))
FAIL_IF(sync_with_child(read_pipe, write_pipe));
FAIL_IF(sync_with_child(read_pipe, write_pipe));
FAIL_IF(sync_with_child(read_pipe, write_pipe));
FAIL_IF(sync_with_child(read_pipe, write_pipe));
FAIL_IF(sync_with_child(read_pipe, write_pipe));
FAIL_IF(sync_with_child(read_pipe, write_pipe));
if (sync_with_child(read_pipe, write_pipe))
FAIL_IF(sync_with_child(read_pipe, write_pipe));
if (sync_with_child(read_pipe, write_pipe))
FAIL_IF(sync_with_child(read_pipe, write_pipe));
if (sync_with_child(read_pipe, write_pipe)) {
extern int sync_with_child(union pipe read_pipe, union pipe write_pipe);