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IP_ADD_MEMBERSHIP(2const) IP_ADD_MEMBERSHIP(2const)

NAME

IP_ADD_MEMBERSHIP - join a multicast group

LIBRARY

Standard C library (libc-lc)

SYNOPSIS

#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>
int setsockopt(int sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
               const struct ip_mreqn *val, sizeof(struct ip_mreqn));

DESCRIPTION

Join a multicast group.

IP_ADD_MEMBERSHIP is valid only for setsockopt(2).

ERRORS

See IPPROTO_IP(2const). See setsockopt(2). See ip(7).

val->imr_multiaddr is not a valid multicast address.

HISTORY

Linux 1.2.

For compatibility, the old ip_mreq structure is still supported. The kernel determines which structure is being passed based on the size passed in the last argument.

SEE ALSO

IPPROTO_IP(2const), ip_mreqn(2type), setsockopt(2), ip(7)

2025-11-25 Linux man-pages (unreleased)