qt 单例程序

1.http://qt.nokia.com的网站把QtSingleApplication 的源代码qtsingleapplication-2.6_1-opensource.zip 下载下来，然后解压缩。假 设解压缩到路径： E:qtsingleapplication-2.6_1-opensource

2.

编写程序代码如下：

#include <QLabel>

#include <QWidget>

#include <QMessageBox>

#include <QApplication>

#include "E:qtsingleapplication-2.6_1-opensourcesrcQtSingleApplication"

int main(int argc,char* argv[])

{

QtSingleApplication app(argc,argv);

if (app.isRunning())

{

QMessageBox::information(0, "test",

"An instance has already been running.");

return 0;

}

QLabel label("<h2>test</h2>");

label.show();

return app.exec();

}

3.

编译

qmake –project

qmake

nmake

第二种方案:

QApplicationapp(argc,argv);

HANDLEhMutex=CreateMutex(NULL,true,QString("['{EFEB2EF6-F8E0-AE44-BABE-1BBEF2C7FD56}']").toStdWString().c_str());

if(GetLastError()==ERROR_ALREADY_EXISTS)

{

CloseHandle(hMutex);

QMessageBox::information(NULL,QObject::tr("error"),QObject::tr("一个实例已经在运行，请关闭后重新打开"),"OK");

app.exit(1);

return1;

}