qt 调试语句的处理 禁用和重定向到文件

#include<QDebug>
int main(int argc, char *argv[])
{
    qDebug()<<"hello qDebug";
    qWarning()<<"hello qWarning";
    qCritical()<<"hello qCritical";
//    qFatal()   <<"hello qFatal"; //can use like this
    qFatal("hello qFatal"); // will exit the program
}

#include <QtDebug>
#include <QFile>
#include <QTextStream>
 
void customMessageHandler(QtMsgType type, const char *msg)
{
	QString txt;
	switch (type) {
	case QtDebugMsg:
		txt = QString("Debug: %1").arg(msg);
		break;
 
	case QtWarningMsg:
		txt = QString("Warning: %1").arg(msg);
	break;
	case QtCriticalMsg:
		txt = QString("Critical: %1").arg(msg);
	break;
	case QtFatalMsg:
		txt = QString("Fatal: %1").arg(msg);
		abort();
	}
 
	QFile outFile("debuglog.txt");
	outFile.open(QIODevice::WriteOnly | QIODevice::Append);
	QTextStream ts(&outFile);
	ts << txt << endl;
}
 
int main( int argc, char * argv[] )
{
	QApplication app( argc, argv );
 
	//Lets register our custom handler, before we start       
	qInstallMsgHandler(customMessageHandler);	
	...
	return app.exec();
}