QPrinter: Must construct a QCoreApplication before a QPrinter
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On Windows with Qt version 5.6, the following line causes my program to stop :
QPrinter * printer = new QPrinter(QPrinter::HighResolution);With the following message in the debugger's Output window :
QPrinter: Must construct a QCoreApplication before a QPrinterSince at the time this happens my application is already long past initialization and the event loop has already treated thousands of events and is certainly not missing, I find this message quite puzzling.
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Hi
Can you reproduce this in small sample?
Could just be a 5.6 bug :) -
Unfortunately, it cannot be reproduced in a simple project.
My guess would be some conflict with some system library that I'm linking to.For some reason I cannot debug into this line without going into disassembly mode, which is too hopeless.
Any advice for debugging it? -
HI
But do you do anything kinky with the QApplication ?
or does the system library contains event loops also.
Else I dont see why it should complain.I guess I would look in source to see if I can
get more information about when it gives this error.also go look in bugs system
https://bugreports.qt.io/browse/QTBUG-43877?jql=text ~ "QPrinter" -
HI
But do you do anything kinky with the QApplication ?
or does the system library contains event loops also.
Else I dont see why it should complain.I guess I would look in source to see if I can
get more information about when it gives this error.also go look in bugs system
https://bugreports.qt.io/browse/QTBUG-43877?jql=text ~ "QPrinter" -
Found it - yes, I did a kinky thing.
If anyone ever stumbles upon this one - it comes from linking a debug build with Qt5PrintSupport.lib. A debug build needs to link with Qt5PrintSupportd.lib, or strange things will happen.
