view test/testlock.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 c121d94672cb
children 4436464c4f51
line wrap: on
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/* Test the thread and mutex locking functions 
   Also exercises the system's signal/thread interaction
*/

#include <signal.h>
#include <stdio.h>

#include "SDL.h"
#include "SDL_mutex.h"
#include "SDL_thread.h"

static SDL_mutex *mutex = NULL;
static Uint32 mainthread;
static SDL_Thread *threads[6];
static volatile int doterminate = 0;

/*
 * SDL_Quit() shouldn't be used with atexit() directly because
 *  calling conventions may differ...
 */
static void
SDL_Quit_Wrapper(void)
{
    SDL_Quit();
}

void
printid(void)
{
    printf("Process %u:  exiting\n", SDL_ThreadID());
}

void
terminate(int sig)
{
    signal(SIGINT, terminate);
    doterminate = 1;
}

void
closemutex(int sig)
{
    Uint32 id = SDL_ThreadID();
    int i;
    printf("Process %u:  Cleaning up...\n", id == mainthread ? 0 : id);
    for (i = 0; i < 6; ++i)
        SDL_KillThread(threads[i]);
    SDL_DestroyMutex(mutex);
    exit(sig);
}

int SDLCALL
Run(void *data)
{
    if (SDL_ThreadID() == mainthread)
        signal(SIGTERM, closemutex);
    while (1) {
        printf("Process %u ready to work\n", SDL_ThreadID());
        if (SDL_mutexP(mutex) < 0) {
            fprintf(stderr, "Couldn't lock mutex: %s", SDL_GetError());
            exit(1);
        }
        printf("Process %u, working!\n", SDL_ThreadID());
        SDL_Delay(1 * 1000);
        printf("Process %u, done!\n", SDL_ThreadID());
        if (SDL_mutexV(mutex) < 0) {
            fprintf(stderr, "Couldn't unlock mutex: %s", SDL_GetError());
            exit(1);
        }
        /* If this sleep isn't done, then threads may starve */
        SDL_Delay(10);
        if (SDL_ThreadID() == mainthread && doterminate) {
            printf("Process %u:  raising SIGTERM\n", SDL_ThreadID());
            raise(SIGTERM);
        }
    }
    return (0);
}

int
main(int argc, char *argv[])
{
    int i;
    int maxproc = 6;

    /* Load the SDL library */
    if (SDL_Init(0) < 0) {
        fprintf(stderr, "%s\n", SDL_GetError());
        exit(1);
    }
    atexit(SDL_Quit_Wrapper);

    if ((mutex = SDL_CreateMutex()) == NULL) {
        fprintf(stderr, "Couldn't create mutex: %s\n", SDL_GetError());
        exit(1);
    }

    mainthread = SDL_ThreadID();
    printf("Main thread: %u\n", mainthread);
    atexit(printid);
    for (i = 0; i < maxproc; ++i) {
        if ((threads[i] = SDL_CreateThread(Run, NULL)) == NULL)
            fprintf(stderr, "Couldn't create thread!\n");
    }
    signal(SIGINT, terminate);
    Run(NULL);

    return (0);                 /* Never reached */
}