• SDLNet_CheckSockets

SDLNet_CheckSockets

Name

SDLNet_CheckSockets -- check all sockets in the socket set for activity.

Synopsis

#include "SDL_net.h"

int SDLNet_CheckSockets(SDLNet_SocketSet set, Uint32 timeout);

set is the socket set to check.

timeout is the maximum amount of time to wait (in milliseconds). 0 means no waiting. -1 means to wait over 49 days! (think about it)

Description

SDLNet_CheckSockets check all sockets in the socket set for activity. If a non-zero timeout is given then this function will wait for activity, or else it will wait for timeout milliseconds.

Note: "activity" also includes disconnections and other errors, which would be determined by a failed read/write attempt.

Return Value

Returns the number of sockets with activity. -1 is returned on errors, and you may not get a meaningful error message. -1 is also returned for an empty set (nothing to check).

Example

// Wait for up to 1 second for network activity
//SDLNet_SocketSet set;
int numready;

numready = SDLNet_CheckSockets(set, 1000);
if (numready == -1) {
    printf("SDLNet_CheckSockets: %s\n", SDLNet_GetError());
    //most of the time this is a system error, where perror might help you.
    perror("SDLNet_CheckSockets");
}
else if (numready) {
    printf("There are %d sockets with activity!\n", numready);
    // check all sockets with SDLNet_SocketReady and handle the active ones.
}

See Also

SDLNet_SocketReady, SDLNet_AddSocket, SDLNet_DelSocket, SDLNet_AllocSocketSet, SDLNet_SocketSet, UDPsocket, TCPsocket