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Thread: Why does qmake/moc only process header files?

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    Default Why does qmake/moc only process header files?

    I was wondering, why qmake/moc only processes header (*.h) files and not source (*.cpp) files?
    I just wonted to declare a class locally in a source module and discovered, that no moc files have been generated.
    Why this restriction and how should it be worked around?
    Thank you,
    Dieter

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    Default Re: Why does qmake/moc only process header files?

    It only looks at *.h files because that is where classes are usually defined. The work around is to define your "private" class in a .h file.

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    doberkofler (2nd March 2010)

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    Default Re: Why does qmake/moc only process header files?

    If you want a private class that is local to a file, then create a private header file only included by that source file. For example, myfile_internal.h and define your classes there.

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    doberkofler (2nd March 2010)

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    Default Re: Why does qmake/moc only process header files?

    There is a better way. If your implementation file that contains a local class is called xyz.cpp then write this under the class declaration:
    Qt Code:
    1. #include "xyz.moc"
    To copy to clipboard, switch view to plain text mode 
    This instructs qmake to force running moc on xyz.cpp. Remember to rerun qmake after you add this statement.

    Qt Code:
    1. class MyLocalClass : public QObject {
    2. Q_OBJECT
    3. public:
    4. // ...
    5. };
    6.  
    7. #include "myfile.moc"
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    Default Re: Why does qmake/moc only process header files?

    I'm not sure if I understand you correctly. Does the include xyz.moc have to to exist and what should it contain?

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    Default Re: Why does qmake/moc only process header files?

    I believe the only reason it is there is that when the makefile is rebuilt it will automatically create a rule to parse the cpp file using MOC, as qmake will parse cpp files for #include lines for dependancy purposes.

    Some people also state that doing so can reduce compilation time: http://edu.kde.org/development/tips....emyfilemoccode
    There some discussion about it on the Qt interest archive: http://lists.trolltech.com/qt-intere...ad00793-0.html
    And it seems to be used more in KDE: http://www.kdevelop.org/3.0/doc/tutorial_settings/#p1

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    Default Re: Why does qmake/moc only process header files?

    For me it's just a matter of convinience that I don't have to create separate header files just to declare local classes.
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

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