From 818db89caa4a315d6f128ff76a24876aad23cd63 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sun, 17 May 2026 15:26:13 -0400
Subject: [PATCH] docs/hello.c: Replaced with a cutdown version of
examples/echo-server.c
Reference Issue #125.
---
docs/hello.c | 99 +++++++++++++++++++++++++++++++++++++---------------
1 file changed, 71 insertions(+), 28 deletions(-)
diff --git a/docs/hello.c b/docs/hello.c
index f842d0c..008ac8f 100644
--- a/docs/hello.c
+++ b/docs/hello.c
@@ -9,43 +9,86 @@
including commercial applications, and to alter it and redistribute it
freely.
*/
-#define SDL_MAIN_USE_CALLBACKS 1 /* use the callbacks instead of main() */
+
+/* this creates a stream socket server, waits for connections, then
+ echoes back anything they send. Connect to the server with telnet
+ or netcat on port 7241 and type things! */
+
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>
#include <SDL3_net/SDL_net.h>
-static SDL_Window *window = NULL;
-static SDL_Renderer *renderer = NULL;
-
-/* This function runs once at startup. */
-SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
+int main(int argc, char **argv)
{
- /* Create the window */
- if (!SDL_CreateWindowAndRenderer("Hello World", 800, 600, SDL_WINDOW_FULLSCREEN, &window, &renderer)) {
- SDL_Log("Couldn't create window and renderer: %s\n", SDL_GetError());
- return SDL_APP_FAILURE;
+ const int SERVER_PORT = 7241;
+
+ if (!NET_Init()) {
+ SDL_Log("NET_Init failed: %s\n", SDL_GetError());
+ SDL_Quit();
+ return 1;
}
- return SDL_APP_CONTINUE;
-}
+ NET_Server *server = NET_CreateServer(NULL, SERVER_PORT, 0);
+ if (!server) {
+ SDL_Log("Failed to create server: %s", SDL_GetError());
+ } else {
+ SDL_Log("Server is ready! Connect to port %d and send text!", (int) SERVER_PORT);
+ int num_vsockets = 1;
+ void *vsockets[128];
+ SDL_zeroa(vsockets);
+ vsockets[0] = server;
+ while (NET_WaitUntilInputAvailable(vsockets, num_vsockets, -1) >= 0) {
+ NET_StreamSocket *streamsocket = NULL;
+ if (!NET_AcceptClient(server, &streamsocket)) {
+ SDL_Log("NET_AcceptClient failed: %s", SDL_GetError());
+ break;
+ } else if (streamsocket) { // new connection!
+ SDL_Log("New connection from %s!", NET_GetAddressString(NET_GetStreamSocketAddress(streamsocket)));
+ if (num_vsockets >= (int) (SDL_arraysize(vsockets) - 1)) {
+ SDL_Log(" (too many connections, though, so dropping immediately.)");
+ NET_DestroyStreamSocket(streamsocket);
+ } else {
+ vsockets[num_vsockets++] = streamsocket;
+ }
+ }
-/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
-SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
-{
- if (event->type == SDL_EVENT_KEY_DOWN ||
- event->type == SDL_EVENT_QUIT) {
- return SDL_APP_SUCCESS; /* end the program, reporting success to the OS. */
+ // see if anything has new stuff.
+ char buffer[1024];
+ for (int i = 1; i < num_vsockets; i++) {
+ bool kill_socket = false;
+ streamsocket = (NET_StreamSocket *) vsockets[i];
+ const int br = NET_ReadFromStreamSocket(streamsocket, buffer, sizeof (buffer));
+ if (br < 0) { // uhoh, socket failed!
+ kill_socket = true;
+ } else if (br > 0) {
+ const char *addrstr = NET_GetAddressString(NET_GetStreamSocketAddress(streamsocket));
+ SDL_Log("Got %d more bytes from '%s'", br, addrstr);
+ if (!NET_WriteToStreamSocket(streamsocket, buffer, br)) {
+ SDL_Log("Failed to echo data back to '%s': %s", addrstr, SDL_GetError());
+ kill_socket = true;
+ }
+ }
+
+ if (kill_socket) {
+ SDL_Log("Dropping connection to '%s'", NET_GetAddressString(NET_GetStreamSocketAddress(streamsocket)));
+ NET_DestroyStreamSocket(streamsocket);
+ vsockets[i] = NULL;
+ if (i < (num_vsockets - 1)) {
+ SDL_memmove(&vsockets[i], &vsockets[i+1], sizeof (vsockets[0]) * ((num_vsockets - i) - 1));
+ }
+ num_vsockets--;
+ i--;
+ }
+ }
+ }
+
+ SDL_Log("Destroying server...");
+ NET_DestroyServer(server);
}
- return SDL_APP_CONTINUE;
-}
-/* This function runs once per frame, and is the heart of the program. */
-SDL_AppResult SDL_AppIterate(void *appstate)
-{
- return SDL_APP_CONTINUE;
+ SDL_Log("Shutting down...");
+ NET_Quit();
+ SDL_Quit();
+ return 0;
}
-/* This function runs once at shutdown. */
-void SDL_AppQuit(void *appstate, SDL_AppResult result)
-{
-}