test/testsem.c

   1
   2 /* Simple test of the SDL semaphore code */
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <signal.h>
   7
   8 #include "SDL.h"
   9 #include "SDL_thread.h"
  10
  11 #define NUM_THREADS 10
  12
  13 static SDL_sem *sem;
  14 int alive = 1;
  15
  16 int SDLCALL ThreadFunc(void *data)
  17 {
  18         int threadnum = (int)(uintptr_t)data;
  19         while ( alive ) {
  20                 SDL_SemWait(sem);
  21                 fprintf(stderr, "Thread number %d has got the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem));
  22                 SDL_Delay(200);
  23                 SDL_SemPost(sem);
  24                 fprintf(stderr, "Thread number %d has released the semaphore (value = %d)!\n", threadnum, SDL_SemValue(sem));
  25                 SDL_Delay(1); /* For the scheduler */
  26         }
  27         printf("Thread number %d exiting.\n", threadnum);
  28         return 0;
  29 }
  30
  31 static void killed(int sig)
  32 {
  33         alive = 0;
  34 }
  35
  36 int main(int argc, char **argv)
  37 {
  38         SDL_Thread *threads[NUM_THREADS];
  39         uintptr_t i;
  40         int init_sem;
  41
  42         if(argc < 2) {
  43                 fprintf(stderr,"Usage: %s init_value\n", argv[0]);
  44                 return(1);
  45         }
  46
  47         /* Load the SDL library */
  48         if ( SDL_Init(0) < 0 ) {
  49                 fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
  50                 return(1);
  51         }
  52         signal(SIGTERM, killed);
  53         signal(SIGINT, killed);
  54
  55         init_sem = atoi(argv[1]);
  56         sem = SDL_CreateSemaphore(init_sem);
  57
  58         printf("Running %d threads, semaphore value = %d\n", NUM_THREADS, init_sem);
  59         /* Create all the threads */
  60         for( i = 0; i < NUM_THREADS; ++i ) {
  61                 threads[i] = SDL_CreateThread(ThreadFunc, (void*)i);
  62         }
  63
  64         /* Wait 10 seconds */
  65         SDL_Delay(10 * 1000);
  66
  67         /* Wait for all threads to finish */
  68         printf("Waiting for threads to finish\n");
  69         alive = 0;
  70         for( i = 0; i < NUM_THREADS; ++i ) {
  71                 SDL_WaitThread(threads[i], NULL);
  72         }
  73         printf("Finished waiting for threads\n");
  74
  75         SDL_DestroySemaphore(sem);
  76         SDL_Quit();
  77         return(0);
  78 }