rt-thread/examples/libc/sem.c

#include <pthread.h>
#include <semaphore.h>
#include <stdio.h>

static sem_t sema;
static void* other_thread()
{
    printf("other_thread here!\n");

    sleep(1);

    while (1)
    {
        printf("other_thread: sem_post...\n");
        if(sem_post(&sema) == -1)
            printf("sem_post failed\n");
        sleep(1);
    }

    printf("other_thread dies!\n");
    pthread_exit(0);
}

static void test_thread(void* parameter)
{
    pthread_t tid;

    printf("main thread here!\n");
    printf("sleep 5 seconds...");
    sleep(5);
    printf("done\n");

    sem_init(&sema, 0, 0);

    /* create the "other" thread */
    if(pthread_create(&tid, 0, &other_thread, 0)!=0)
        /* error */
        printf("pthread_create OtherThread failed.\n");
    else
        printf("created OtherThread=%x\n", tid);

    /* let the other thread run */
    while (1)
    {
        printf("Main: sem_wait...\n");
        if(sem_wait(&sema) == -1)
            printf("sem_wait failed\n");
        printf("Main back.\n\n");
    }

    pthread_exit(0);
}
#include <finsh.h>
void libc_sem()
{
    rt_thread_t tid;

    tid = rt_thread_create("semtest", test_thread, RT_NULL,
        2048, 20, 5);
    if (tid != RT_NULL)
    {
        rt_thread_startup(tid);
    }
}
FINSH_FUNCTION_EXPORT(libc_sem, posix semaphore test);