msgsnap
if (msgsnap(msqid, buf, bufsize, mtype) != 0) {
error = msgsnap((int)a1, (caddr_t)a2, (size_t)a3, (long)a4);
error = msgsnap((int)a1, (caddr_t)(uintptr_t)a2, (size_t)a3,
int msgsnap(int, void *, size_t, long);