/* ...and wait for filter process to finish. */
int status;
waitpid(filter_pid, &status, 0);
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
/* ...and wait for filter process to finish. */
int status;
waitpid(filter_pid, &status, 0);
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {