Plan 9 from Bell Labs’s /usr/web/sources/contrib/anothy/src/lib/djb-ape/unix/socket_mcloop4.c
#include <sys/types.h> #include <sys/param.h> #include <sys/socket.h> #include <netinet/in.h> #include "socket.h" int socket_mcloop4(int s,char loop) { return setsockopt(s,IPPROTO_IP,/*IP_MULTICAST_LOOP*/ 0,&loop,sizeof loop); }