include

[mickey]

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

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

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

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[jacek]

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.

[mickey]

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

[jacek]

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

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

[mickey]

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

[jacek]

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

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".

[wysota]

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