使用Qt时如何打印到控制台
我正在使用 Qt4 和 C++ 来制作一些计算机图形程序.我需要能够在运行时在我的控制台中打印一些变量,而不是调试,但是即使我添加了库,cout
似乎也不起作用.有没有办法做到这一点?
I'm using Qt4 and C++ for making some programs in computer graphics. I need to be able to print some variables in my console at run-time, not debugging, but cout
doesn't seem to work even if I add the libraries. Is there a way to do this?
推荐答案
如果打印到 stderr
足够好,您可以使用以下最初用于调试的流:
If it is good enough to print to stderr
, you can use the following streams originally intended for debugging:
#include<QDebug>
//qInfo is qt5.5+ only.
qInfo() << "C++ Style Info Message";
qInfo( "C Style Info Message" );
qDebug() << "C++ Style Debug Message";
qDebug( "C Style Debug Message" );
qWarning() << "C++ Style Warning Message";
qWarning( "C Style Warning Message" );
qCritical() << "C++ Style Critical Error Message";
qCritical( "C Style Critical Error Message" );
// qFatal does not have a C++ style method.
qFatal( "C Style Fatal Error Message" );
尽管如评论中所指出的,请记住,如果定义了 QT_NO_DEBUG_OUTPUT
,则会删除 qDebug 消息
Though as pointed out in the comments, bear in mind qDebug messages are removed if QT_NO_DEBUG_OUTPUT
is defined
如果你需要标准输出,你可以尝试这样的事情(正如凯尔斯特兰德指出的那样):
If you need stdout you could try something like this (as Kyle Strand has pointed out):
QTextStream& qStdOut()
{
static QTextStream ts( stdout );
return ts;
}
然后您可以按如下方式调用:
You could then call as follows:
qStdOut() << "std out!";
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