This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
testsem.c
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/* Simple test of the SDL semaphore code */
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include "SDL.h"
#include "SDL_thread.h"
#define NUM_THREADS 10
static SDL_sem *sem;
int alive = 1;
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ThreadFunc(void *data)
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int threadnum = (int) (uintptr_t) data;
while (alive) {
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SDL_SemWait(sem);
fprintf(stderr,
"Thread number %d has got the semaphore (value = %d)!\n",
threadnum, SDL_SemValue(sem));
SDL_Delay(200);
SDL_SemPost(sem);
fprintf(stderr,
"Thread number %d has released the semaphore (value = %d)!\n",
threadnum, SDL_SemValue(sem));
SDL_Delay(1); /* For the scheduler */
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printf("Thread number %d exiting.\n", threadnum);
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}
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killed(int sig)
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}
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main(int argc, char **argv)
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SDL_Thread *threads[NUM_THREADS];
uintptr_t i;
int init_sem;
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if (argc < 2) {
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fprintf(stderr, "Usage: %s init_value\n", argv[0]);
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return (1);
}
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/* Load the SDL library */
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if (SDL_Init(0) < 0) {
fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
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return (1);
}
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signal(SIGTERM, killed);
signal(SIGINT, killed);
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init_sem = atoi(argv[1]);
sem = SDL_CreateSemaphore(init_sem);
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printf("Running %d threads, semaphore value = %d\n", NUM_THREADS,
init_sem);
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/* Create all the threads */
for (i = 0; i < NUM_THREADS; ++i) {
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threads[i] = SDL_CreateThread(ThreadFunc, (void *) i);
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/* Wait 10 seconds */
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SDL_Delay(10 * 1000);
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/* Wait for all threads to finish */
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printf("Waiting for threads to finish\n");
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alive = 0;
for (i = 0; i < NUM_THREADS; ++i) {
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SDL_WaitThread(threads[i], NULL);
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printf("Finished waiting for threads\n");
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SDL_DestroySemaphore(sem);
SDL_Quit();