Qt进程单例

利用共享内存通信，第二次打开程序时，激活第一次打开的进程

#include <QApplication>
#include <QSharedMemory>
#include <QTimer>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);	

	QSharedMemory shareMem("Rayvision StartPlayTool");
	if (!shareMem.create(1))
	{
		if (shareMem.attach(QSharedMemory::ReadWrite) && shareMem.lock())
		{
			*static_cast<uint8_t *>(shareMem.data()) = 1;
			shareMem.unlock();
		}
		return -1;
	}
    
    // ... 用户代码
    
    QTimer timer;
	timer.callOnTimeout([&] {
		shareMem.lock();

		if (*static_cast<uint8_t *>(shareMem.data()) != 0)
		{
			// ... 激活窗口
			*static_cast<uint8_t *>(shareMem.data()) = 0;
		}

		shareMem.unlock();
	});
	timer.start(10);
    
    return a.exec();
}