SDL Wiki
(This function is part of SDL_net, a separate library from SDL.)


Send bytes over a stream socket to a remote system.

Header File

Defined in <SDL3_net/SDL_net.h>


int SDLNet_WriteToStreamSocket(SDLNet_StreamSocket *sock, const void *buf, int buflen);

Function Parameters

SDLNet_StreamSocket * sock the stream socket to send data through.
const void * buf a pointer to the data to send.
int buflen the size of the data to send, in bytes.

Return Value

(int) Returns 0 if data sent or queued for transmission, -1 on failure; call SDL_GetError() for details.


Stream sockets are reliable, which means data sent over them will arrive in the order it was transmitted, and the system will retransmit data as necessary to ensure its delivery. Which is to say, short of catastrophic failure, data will arrive, possibly with severe delays. Also, "catastrophic failure" isn't an uncommon event.

(This is opposed to Datagram sockets, which send chunks of data that might arrive in any order, or not arrive at all, but you never wait for missing chunks to show up.)

Stream sockets are bidirectional; you can read and write from the same stream, and the other end of the connection can, too.

This call never blocks; if it can't send the data immediately, the library will queue it for later transmission. You can use SDLNet_GetStreamSocketPendingWrites() to see how much is still queued for later transmission, or SDLNet_WaitUntilStreamSocketDrained() to block until all pending data has been sent.

If the connection has failed (remote side dropped us, or one of a million other networking failures occurred), this function will report failure by returning -1. Stream sockets only report failure for unrecoverable conditions; once a stream socket fails, you should assume it is no longer usable and should destroy it with SDL_DestroyStreamSocket().

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.


This function is available since SDL_Net 3.0.0.

See Also

CategoryAPI, CategoryAPIFunction

[ edit | delete | history | feedback | raw ]

[ front page | index | search | recent changes | git repo | offline html ]

All wiki content is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0).
Wiki powered by ghwikipp.