Socket tips: 同意socket发送UDP Broadcast

假设创建一个UDP Socket：

socketHandle = socket(serverAddr->ai_family, serverAddr->ai_socktype, serverAddr->ai_protocol);

如今就用它来发送Broadcast。一定会出错的，Socket API不同意这样做。那么怎样使它支持broadcast呢？须要继续做一些设置：

int broadcastPermission = 1;

setsockopt(socketHandle, SOL_SOCKET, SO_BROADCAST, (void *) &broadcastPermission, sizeof(broadcastPermission));

完整的UDP broadcast的样例见：《Socket tips: UDP Echo service - Client code》