Linux Qt只能运行一个实例的完美方案

程序名称可以被改

#include <QApplication>

#include <QLocalSocket>

#include <QLocalServer>

#include <QFile>

#include <limits.h>

#include <stdio.h>

#include <string.h>

#include <unistd.h>

size_t get_executable_path( char* processdir,char* processname, size_t len)

{

    char* path_end;

    if(readlink("/proc/self/exe", processdir,len) <=0)

        return -1;

    path_end = strrchr(processdir,  '/');

    if(path_end == NULL)

        return -1;

    ++path_end;

    strcpy(processname, path_end );

    *path_end = '\0';

    return (size_t)(path_end - processdir);

}

bool is_running;

QLocalServer *server;

void checkSinglt()

{

    char path[200];

    char processname[50];

    memset( path, 0, 200 );

    memset( processname, 0, 50 );

    std::cout<<"@@@ @@###### Check Instance!!! #######@@ @@@"<<std::endl;

    is_running = false;

    size_t sizx = get_executable_path( path, processname, sizeof(path) );

    QCoreApplication::setApplicationName(processname);

    QString serverName = QCoreApplication::applicationName();

    QLocalSocket socket;

    socket.connectToServer(serverName);

    if(socket.waitForConnected(500))

    {

        is_running =true;

        return;

    }

    //连接不上服务器，就创建一个

    server =new QLocalServer();

    // connect(server, SIGNAL(newConnection()), this,SLOT(newLocalConnection()));

    if(server->listen(serverName))

    {

        //防止程序崩溃时,残留进程服务,移除之

        if( server->serverError() == QAbstractSocket::AddressInUseError &&QFile::exists(server->serverName()))

        {

            QFile::remove(server->serverName());

            server->listen(serverName);

        }

    }

}

#include <QMessageBox>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    checkSinglt();
    if(is_running)
    {
        std::cout<<"@@@ Error Exist Instance"<<std::endl;
        QMessageBox::information(NULL, "Singnlt", "Error Already Has An Instance!!!", QMessageBox::Ok);
        exit(0);
    }
    return a.exec(); 
}