include

Hi, I have seen this line at the end of a main.cpp. What does this do? Thanks

Code:

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//main.cpp
.........
#include "main.moc"

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It tells qmake to run moc on this file and generate "main.moc" with implementation of the signals and slots mechanism. You must use it when you place class definition with Q_OBJECT macro in a .cpp file.

sorrry, but when do I need to put a class in main.ccp instead of in a apart file? thanks

Quote:

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Originally Posted by mickey

sorrry, but when do I need to put a class in main.ccp instead of in a apart file? thanks

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You put class definitions in .cpp file only when you don't want them to be visible outside that file.

but Is there a pratical reason to hide a class into a .cpp? Why to hide?
Thanks

Quote:

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Originally Posted by mickey

but Is there a pratical reason to hide a class into a .cpp? Why to hide?

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For example when you are writing a library, you might want to hide the implementation, so that after every change you don't have to recompile all programs that use that library. Ask google about "pimpl" or "d pointer".

Or when you are lazy and don't want to create three files instead of one. :cool: