Protocol Names – protoent

The protoent structure defines the protocol-name mapping used with getprotobyname(3SOCKET), getprotobynumber(3SOCKET), and getprotoent(3SOCKET) and defined in getprotoent(3SOCKET):

struct protoent {
    char    *p_name;       /* official protocol name */
    char    **p_aliases    /* alias list */
    int     p_proto;       /* protocol number */
};