sending and recieveing packets with dynamic size.

if i have a packet like so

Code:

---

struct PACKET
{
    unsigned char command;
    unsigned short length;
    char* message;
};

---

i know how to send it, but how would i recieve it? since i dont know the size of the packet before i recv() it?

http://cboard.cprogramming.com/showthread.php?t=79633