set_ip_dscp
err = set_ip_dscp(s, family, dscp);
err = set_ip_dscp(s, addr->ai_family, dscp);
char* set_ip_dscp(int socket, int addrfamily, int ds);
err = set_ip_dscp(s, af, dscp);
err = set_ip_dscp(s, family, dscp);
err = set_ip_dscp(s, addr->ai_family, dscp);
char* set_ip_dscp(int socket, int addrfamily, int ds);
err = set_ip_dscp(s, af, dscp);