###### (This function is part of SDL_net, a separate library from SDL.) # SDLNet_ReceiveDatagram Receive a new packet that a remote system sent to a datagram socket. ## Header File Defined in [](https://github.com/libsdl-org/SDL_net/blob/main/include/SDL3_net/SDL_net.h) ## Syntax ```c bool SDLNet_ReceiveDatagram(SDLNet_DatagramSocket *sock, SDLNet_Datagram **dgram); ``` ## Function Parameters | | | | | ------------------------------------------------ | --------- | ----------------------------------------- | | [SDLNet_DatagramSocket](SDLNet_DatagramSocket) * | **sock** | the datagram socket to send data through. | | [SDLNet_Datagram](SDLNet_Datagram) ** | **dgram** | a pointer to the datagram packet pointer. | ## Return Value (bool) Returns true if data sent or queued for transmission, false on failure; call SDL_GetError() for details. ## Remarks Datagram sockets send packets of data. They either arrive as complete packets or they don't arrive at all, so you'll never receive half a packet. This call never blocks; if no new data isn't available at the time of the call, it returns 0 immediately. The caller can try again later. On a successful call to this function, it returns zero, even if no new packets are available, so you should check for a successful return and a non-NULL value in `*dgram` to decide if a new packet is available. You must pass received packets to [SDLNet_DestroyDatagram](SDLNet_DestroyDatagram) when you are done with them. If you want to save the sender's address past this time, it is safe to call [SDLNet_RefAddress](SDLNet_RefAddress)() on the address and hold onto the pointer, so long as you call [SDLNet_UnrefAddress](SDLNet_UnrefAddress)() on it when you are done with it. Since datagrams can arrive from any address or port on the network without prior warning, this information is available in the [SDLNet_Datagram](SDLNet_Datagram) object that is provided by this function, and this is the only way to know who to reply to. Even if you aren't acting as a "server," packets can still arrive at your socket if someone sends one. If there's a fatal error, this function will return false. Datagram sockets generally won't report failures, because there is no state like a "connection" to fail at this level, but may report failure for unrecoverable system-level conditions; once a datagram socket fails, you should assume it is no longer usable and should destroy it with SDL_DestroyDatagramSocket(). ## Thread Safety You should not operate on the same socket from multiple threads at the same time without supplying a serialization mechanism. However, different threads may access different sockets at the same time without problems. ## Version This function is available since SDL_Net 3.0.0. ## See Also - [SDLNet_SendDatagram](SDLNet_SendDatagram) - [SDLNet_DestroyDatagram](SDLNet_DestroyDatagram) ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction)