.TH socket_mcloop4 3 .SH NAME socket_mcloop4 \- set multicast loopback .SH SYNTAX .B #include int \fBsocket_mcloop4\fP(int \fIs\fR,char \fIloop\fR); .SH DESCRIPTION socket_mcloop4 activates multicast loopback for the socket \fIs\fR if \fIloop\fR is non-zero, and deactivates it otherwise. If loopback is activated, packets sent on this socket will be received on the same host. If something goes wrong, socket_mcloop4 returns -1, setting errno appropriately. .SH "SEE ALSO" socket_mcloop6(3), socket_mcjoin4(3), socket_mcleave4(3)