QtSingleApplication

​​​​​​/qtsingleapplication/

qtSingleApplication使用总结-CSDN博客

示例：

#include "mainwindow.h"
#include <QApplication>
#include <QMessageBox>
#include "qtsingleapplication/qtsingleapplication.h"
int main(int argc, char *argv[])
{
    QtSingleApplication singleApp("test",argc,argv);
    if(singleApp.isRunning())
    {
        QMessageBox::information(nullptr,"提示","程序已运行！","确定");
        return -1;
    }
    MainWindow w;
    w.show();

    return singleApp.exec();
}