Do qDebug statements degrade app performance? - Qt

? Offline

Hi,

I have lot of debug statements in my Qt project. The app randomly hangs and crashes. I was wondering if the qDebug statements are degrading the app performance in any manner.

Please suggest.

Thanks

? Offline

I've never had problems with qDebug at all.

Are you sure the app isn't crashing because of bad pointers?

? Offline

Actually i am not. Its the most likely cause but just wanted to be sure about qDebug statements. Thanks

giesbert

qDebug statements will surely slow down the app, as all tracing / debugging statements do.
But it should not be significally.
If the debug statement crashes, it is typically a wrong statement or a wrong parameter.

? Offline

Thanks Gerolf but do they even execute when I am using the app on the phone while I am not debugging?

giesbert

They execute when you build your app with debug support enabled. As I don't know, how you build for the phone, I can't tell you.
If debugging is disabled, they result in NOPs.

? Offline

They execute even if you build your app in release mode. You can even reroute output using qInstallMsgHandler() to write it in file, or send it through network, etc...

SGaist

Hi,

You can define QT_NO_DEBUG_OUTPUT before compiling so that qDebug does nothing