view test/checkkeys.c @ 2318:0c653886cce7

HandleEvent() returns done each time it is called. If done was set to 0 the program should quit, but because done is not checked until *all* events are handled a following event can reset done to 1 and prevent the program from terminating when told to. I fixed the while loop that handles events to check for the state of done after handling each event. That could leave some events unhandled when the program exits, but it ensures that the program will exit.
author Bob Pendleton <bob@pendleton.com>
date Wed, 20 Feb 2008 23:27:33 +0000
parents 95586dfe1992
children 95352c671a6e
line wrap: on
line source


/* Simple program:  Loop, watching keystrokes
   Note that you need to call SDL_PollEvent() or SDL_WaitEvent() to 
   pump the event loop and catch keystrokes.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDL_Quit();
    exit(rc);
}

static void
print_modifiers(void)
{
    int mod;
    printf(" modifiers:");
    mod = SDL_GetModState();
    if (!mod) {
        printf(" (none)");
        return;
    }
    if (mod & KMOD_LSHIFT)
        printf(" LSHIFT");
    if (mod & KMOD_RSHIFT)
        printf(" RSHIFT");
    if (mod & KMOD_LCTRL)
        printf(" LCTRL");
    if (mod & KMOD_RCTRL)
        printf(" RCTRL");
    if (mod & KMOD_LALT)
        printf(" LALT");
    if (mod & KMOD_RALT)
        printf(" RALT");
    if (mod & KMOD_LGUI)
        printf(" LGUI");
    if (mod & KMOD_RGUI)
        printf(" RGUI");
    if (mod & KMOD_NUM)
        printf(" NUM");
    if (mod & KMOD_CAPS)
        printf(" CAPS");
    if (mod & KMOD_MODE)
        printf(" MODE");
}

static void
PrintKey(SDL_keysym * sym, int pressed)
{
    /* Print the keycode, name and state */
    if (sym->sym) {
        printf("Key %s:  scancode %d = %s, keycode 0x%08X = %s ",
               pressed ? "pressed " : "released",
               sym->scancode,
               SDL_GetScancodeName(sym->scancode),
               sym->sym, SDL_GetKeyName(sym->sym));
    } else {
        printf("Unknown Key (scancode %d = %s) %s ",
               sym->scancode,
               SDL_GetScancodeName(sym->scancode),
               pressed ? "pressed" : "released");
    }

    /* Print the translated character, if one exists */
    if (sym->unicode) {
        /* Is it a control-character? */
        if (sym->unicode < ' ') {
            printf(" (^%c)", sym->unicode + '@');
        } else {
#ifdef UNICODE
            printf(" (%c)", sym->unicode);
#else
            /* This is a Latin-1 program, so only show 8-bits */
            if (!(sym->unicode & 0xFF00))
                printf(" (%c)", sym->unicode);
            else
                printf(" (0x%X)", sym->unicode);
#endif
        }
    }
    print_modifiers();
    printf("\n");
}

static void
PrintText(char *text)
{
    printf("Text: %s\n", text);
}

int
main(int argc, char *argv[])
{
    SDL_Event event;
    int done;
    Uint32 videoflags;

    /* Initialize SDL */
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return (1);
    }

    videoflags = SDL_SWSURFACE;
    while (argc > 1) {
        --argc;
        if (argv[argc] && !strcmp(argv[argc], "-fullscreen")) {
            videoflags |= SDL_FULLSCREEN;
        } else {
            fprintf(stderr, "Usage: %s [-fullscreen]\n", argv[0]);
            quit(1);
        }
    }

    /* Set 640x480 video mode */
    if (SDL_SetVideoMode(640, 480, 0, videoflags) == NULL) {
        fprintf(stderr, "Couldn't set 640x480 video mode: %s\n",
                SDL_GetError());
        quit(2);
    }

    /* Watch keystrokes */
    done = 0;
    while (!done) {
        /* Check for events */
        SDL_WaitEvent(&event);
        switch (event.type) {
        case SDL_KEYDOWN:
            PrintKey(&event.key.keysym, 1);
            break;
        case SDL_KEYUP:
            PrintKey(&event.key.keysym, 0);
            break;
        case SDL_TEXTINPUT:
            PrintText(event.text.text);
            break;
        case SDL_MOUSEBUTTONDOWN:
            /* Any button press quits the app... */
        case SDL_QUIT:
            done = 1;
            break;
        default:
            break;
        }
    }

    SDL_Quit();
    return (0);
}