linux网络编程二十七：多线程编程之信号量、互斥锁和条件变量

1. locker.h

#ifndef __LOCKER_H__
#define __LOCKER_H__

#include 
#include 
#include 

class sem
{
public:
    sem()
    {
        if (sem_init(&m_sem, 0, 1) != 0)
            throw std::exception();
    }

    ~sem()
    {
        sem_destroy(&m_sem);
    }

    bool wait() { return sem_wait(&m_sem) == 0; }

    bool post() {return sem_post(&m_sem) == 0; }

private:
    sem_t m_sem;
};

class locker
{
public:
    locker()
    {
        if (pthread_mutex_init(&m_mutex, NULL) != 0)
            throw std::exception();
    }

    ~locker()
    {
        pthread_mutex_destroy(&m_mutex);
    }

    bool lock() { return pthread_mutex_lock(&m_mutex) == 0; }

    bool unlock() { return pthread_mutex_unlock(&m_mutex) == 0; }

private:
    pthread_mutex_t m_mutex;
};


class cond
{
public:
    cond()
    {
        if (pthread_mutex_init(&m_mutex, NULL) != 0)
            throw std::exception();

        if (pthread_cond_init(&m_cond, NULL) != 0) {
            pthread_mutex_destroy(&m_mutex);
            throw std::exception();
        }
    }
    
    ~cond()
    {
        pthread_mutex_destroy(&m_mutex);
        pthread_cond_destroy(&m_cond);
    }

    bool wait() { return pthread_cond_wait(&m_cond, &m_mutex) == 0; }
    bool signal() { return pthread_cond_signal(&m_cond) == 0; }

    bool lock() { return pthread_mutex_lock(&m_mutex) == 0; }
    bool unlock() { return pthread_mutex_unlock(&m_mutex) == 0;}

private:
    pthread_mutex_t m_mutex;
    pthread_cond_t m_cond;
};

#endif

2. test.cpp

#include 
#include 
#include 

#include "locker.h"

static int n = 1;
static sem sem_lock;
static locker lock;
static cond cond_lock;

void* handler(void *arg)
{
    int i = 10;
    while (i>0) {
        sem_lock.wait();
        
        n = 1;
        fprintf(stderr, "other thread %d  n: %d\n", i, n);
        sem_lock.post();
               
        i--;
    }
}

void* result(void *arg)
{
    cond_lock.lock();
    cond_lock.wait();
    fprintf(stderr, "OK...\n");
    cond_lock.unlock();
}

int main(int argc, char *argv[])
{
    pthread_t id1, id2;

    pthread_create(&id1, NULL, handler, NULL);
    pthread_create(&id2, NULL, result, NULL);

    int i = 10;
    while (i>0) {
        sem_lock.wait();
               
        n = 3;
        fprintf(stderr, "main pthread %d  n: %d\n", i, n);
        
        sem_lock.post();        
        
        i--;
    }

    void *status;
    pthread_join(id1, &status);
    
    cond_lock.signal();
    pthread_join(id2, &status);

    return 0;
}

参考：《linux高性能服务器编程》