Qt 多进程通信之消息队列

服务端:

#include            /* For O_* constants */
#include         /* For mode constants */
#include 
#include 
#include 

#define MQNAME  "/fifo1"

mqd_t m_mq;//message queue object
bool bExitThread = false;//exit thread condition
pthread_t g_thread;//thread object

void* Process(void* args)
{
    while(true){
        if(bExitThread){
            break;
        }
        char cData[1024] = {"123"};
        int nSend = mq_send(m_mq, cData, strlen(cData), 0);//nonblock
        if(errno == EAGAIN){
            syslog(LOG_DEBUG, "EAGAIN");
        }
        if(errno == EBADF){
            syslog(LOG_DEBUG, "EBADF");
        }
        if(errno == EINTR){
            syslog(LOG_DEBUG, "EINTR");
        }
        if(errno == EINVAL){
            syslog(LOG_DEBUG, "EINVAL");
        }
        if(errno == EMSGSIZE){
            syslog(LOG_DEBUG, "EMSGSIZE");
        }
        if(errno == ETIMEDOUT){
            syslog(LOG_DEBUG, "ETIMEDOUT");
        }
        usleep(1000 * 1000);//sleep one second
    }
}

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    m_mq = mq_open(MQNAME, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH, NULL);

    mq_attr m_attr;
    mq_getattr(m_mq, &m_attr);// get attribute from mq

    m_attr.mq_flags |= O_NONBLOCK;
    mq_setattr(m_mq, &m_attr, NULL);//set nonblock

    pthread_create(&g_thread, NULL, Process, this);//start thread
}

MainWindow::~MainWindow()
{
    bExitThread = true;//break-thread signal
    pthread_join(g_thread, NULL); //wait thread exit
    mq_close(m_mq); //close mq object
    mq_unlink(MQNAME);//delete mq from kernel
    delete ui;
}

客户端:

#include            /* For O_* constants */
#include         /* For mode constants */
#include 
#include 
#include 
#define MQNAME  "/fifo1"

mqd_t m_mq;
bool bExitThread = false;
pthread_t g_thread;

void* Process(void* args)
{
    while(true){
        if(bExitThread){
            break;
        }
        char cData[8192] = {0};
        ssize_t nRecv = mq_receive(m_mq, cData, 8192, 0);
        if(errno == EAGAIN){
            syslog(LOG_DEBUG, "EAGAIN");
        }
        if(errno == EBADF){
            syslog(LOG_DEBUG, "EBADF");
        }
        if(errno == EINTR){
            syslog(LOG_DEBUG, "EINTR");
        }
        if(errno == EINVAL){
            syslog(LOG_DEBUG, "EINVAL");
        }
        if(errno == EMSGSIZE){
            syslog(LOG_DEBUG, "EMSGSIZE");
        }
        if(errno == ETIMEDOUT){
            syslog(LOG_DEBUG, "ETIMEDOUT");
        }
        usleep(1000 * 1000);
    }
}

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    m_mq = mq_open(MQNAME, O_RDWR | O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH, NULL);
    pthread_create(&g_thread, NULL, Process, this);
}

MainWindow::~MainWindow()
{
    bExitThread = true;
    pthread_join(g_thread, NULL);
    mq_close(m_mq);
    mq_unlink(MQNAME);
    delete ui;
}