信号量

#include <semaphore.h>
#include <fcntl.h>
#include <iostream>
#include <vector>
#include <unistd.h>
using namespace std;

sem_t semProducer,semConsumer;
vector<int> v;

void* producer(void*)
{
    while(1)
    {
        if(v.size()>=5)
        {
            sem_post(&semConsumer);
            sem_wait(&semProducer);
        }else
        {
            v.push_back(1);
            cout << "push,size:" << v.size() << endl;
            sleep(1);
        }
    }
    pthread_detach(pthread_self());
    return 0;
}

void* consumer(void*)
{
    while(1)
    {
        if(v.empty())
        {
            sem_post(&semProducer);
            sem_wait(&semConsumer);
        }else
        {
            v.pop_back();
            cout << "pop,size:" << v.size() << endl;
            sleep(1);
        }
    }
    pthread_detach(pthread_self());
    return 0;
}

int main()
{
    sem_init(&semProducer,0,0);
    sem_init(&semConsumer,0,1);
    pthread_t pidProducer,pidConsumer;
    pthread_create(&pidProducer,NULL,producer,NULL);
    pthread_create(&pidConsumer,NULL,consumer,NULL);
    sleep(10);
    cout << "destroy ret:" << sem_destroy(&semConsumer) << endl;
    cout << "destroy ret:" << sem_destroy(&semProducer) << endl;
}

push,size:1
push,size:2
push,size:3
push,size:4
push,size:5
pop,size:4
pop,size:3
pop,size:2
pop,size:1
pop,size:0
destroy ret:0
destroy ret:0

等待超时终止

#include <semaphore.h>
#include <iostream>
#include <sys/time.h>
#include <unistd.h>
using namespace std;
sem_t sem;

void* testWait(void*)
{
    while(1)
    {
        sleep(10);
        sem_post(&sem);
        cout << "post sem" << endl;
    }
    pthread_detach(pthread_self());
    return 0;
}

int main()
{
    sem_init(&sem,0,0);
    pthread_t pidWait;
    pthread_create(&pidWait,NULL,testWait,NULL);
    struct timespec timeEnd;
    struct timeval timeNow;
    gettimeofday(&timeNow,NULL);
    timeEnd.tv_sec = timeNow.tv_sec+5;
    sem_timedwait(&sem,&timeEnd);
    cout << "wait finished" << endl;
    sleep(10);
    cout << "destroy ret:" << sem_destroy(&sem) << endl;
}

wait finished
post sem
destroy ret:0