条件变量实现的定时器

用条件变量实现的一个简单的定时器，直接上代码吧

#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>
#include <errno.h>

void * tick( void * arg){
    pthread_cond_t cond;
    pthread_mutex_t mutex;
    pthread_mutex_init( &mutex,NULL);
    pthread_cond_init( &cond,NULL);

    struct timespec to;
    int i = 0;
    pthread_mutex_lock( &mutex);

    to.tv_sec = time( NULL) + 1;
    to.tv_nsec = 0;

    while ( i < 5)     {
        int err = pthread_cond_timedwait( &cond, &mutex, &to);
        if ( err == ETIMEDOUT){
            printf( "time out %d: dispatch something...\n",i);
            to.tv_sec = time( NULL) + 1;
            to.tv_nsec = 0;
            i++;
        }
    }

    pthread_mutex_unlock( &mutex);
}

int main( )
{
    pthread_t pid;
    int i=0;
    printf( "create thread.../n");

    pthread_create( &pid,0,tick,0);
    pthread_join( pid,NULL);
    sleep( 1);

    printf( "Succeed exit!/n");

}