Socket.getservbyname

Socket.getservbyname(service_name) => port_number

Socket.getservbyname(service_name, protocol_name) => port_number

static VALUE
sock_s_getservbyname(int argc, VALUE *argv, VALUE _)
{
    VALUE service, proto;
    struct servent *sp;
    long port;
    const char *servicename, *protoname = "tcp";

    rb_scan_args(argc, argv, "11", &service, &proto);
    StringValue(service);
    if (!NIL_P(proto)) StringValue(proto);
    servicename = StringValueCStr(service);
    if (!NIL_P(proto)) protoname = StringValueCStr(proto);
    sp = getservbyname(servicename, protoname);
    if (sp) {
        port = ntohs(sp->s_port);
    }
    else {
        char *end;

        port = STRTOUL(servicename, &end, 0);
        if (*end != '\0') {
            rb_raise(rb_eSocket, "no such service %s/%s", servicename, protoname);
        }
    }
    return INT2FIX(port);
}

Obtains the port number for service_name.

If protocol_name is not given, “tcp” is assumed.

Example

Socket.getservbyname("smtp")          #=> 25
Socket.getservbyname("shell")         #=> 514
Socket.getservbyname("syslog", "udp") #=> 514

See also .getnameinfo .getservbyport .getifaddrs .ip_address_list also in 4.1 · 4.0 · 3.4 · 3.2 · 3.1 · 3.0

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