WNOHANG
while (waitpid(-1, NULL, WNOHANG) > 0);
if (status == B_WOULD_BLOCK && (flags & WNOHANG) == 0)
if (status != B_WOULD_BLOCK || (flags & WNOHANG) != 0) {
waitpid(pid, NULL, WNOHANG);
if (child == B_WOULD_BLOCK && (options & WNOHANG) != 0)
while (waitpid(-1, NULL, WNOHANG) > 0) {