NET_CreateServer(3)

NAME
NET_CreateServer - Create a server, which listens for connections to accept.

SYNOPSIS
#include <SDL3_net/SDL_net.h>

NET_Server * NET_CreateServer(NET_Address *addr, Uint16 port, SDL_PropertiesID props);

#define NET_PROP_SERVER_REUSEADDR_BOOLEAN     "NET.server.reuseaddr"

DESCRIPTION
An app that initiates connection to a remote computer is called a "client," and the thing the client connects to is called a "server."

Servers listen for and accept connections from clients, which spawns a new stream socket on the server's end, which it can then send/receive data on.

Use this function to create a server that will accept connections from other systems.

This function does not block, and is not asynchronous, as the system can decide immediately if it can create a server or not. If this returns success, you can immediately start accepting connections.

You can specify an address to listen for connections on; this address must be local to the system, and probably one returned by NET_GetLocalAddresses(), but almost always you just want to specify NULL here, to listen on any address available to the app.

After creating a server, you get stream sockets to talk to incoming client connections by calling NET_AcceptClient().

Stream sockets don't employ any protocol (above the TCP level), so they can accept connections from clients that aren't using SDL_net, but if you want to speak any protocol beyond an abritrary stream of bytes, such as HTTP, you'll have to implement that yourself on top of the stream socket.

Unlike BSD sockets or WinSock, you specify the port as a normal integer; you do not have to byteswap it into "network order," as the library will handle that for you.

The caller may supply properties to customize behavior. This is optional, and a value of zero for props will request defaults for all properties.

These are the supported properties:

• NET_PROP_SERVER_REUSEADDR_BOOLEAN: true if the server should be created even if a previous server has recently used this address. For various reasons, networks prefer that there be some delay between apps reusing the same address, but this can be problematic when iterating quickly, for software development purposes or just restarting a crashed service. This property defaults to true (although it should be noted that, at the operating system level, this defaults to false!). If this property is false and the OS feels that not enough time has elapsed, server creation will fail and this function will report an error.

FUNCTION PARAMETERS

addr
    the _local_ address to listen for connections on, or NULL.

port
    the port on the local address to listen for connections on.

props
    properties of the new server. Specify zero for defaults.

RETURN VALUE
Returns a new NET_Server, or NULL on error; call SDL_GetError() for details.

THREAD SAFETY
It is safe to call this function from any thread.

AVAILABILITY
This function is available since SDL_net 3.0.0.

SEE ALSO
NET_GetLocalAddresses(3), NET_AcceptClient(3), NET_DestroyServer(3)