when should Generating "moc" files in qt project,and what is the "moc" files's function？
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I create a new qt project in Mac qt for test the example in :http://doc.qt.io/archives/qt-4.8/signalsandslots.html#signals-and-slots
for test the 'Signals & Slots', it seem it will generated moc_counter.cpp.o,moc_predefs.h,moc_counter.o "moc" files in the "-Deubg" directory after build,I delete the "moc" files,and I run the project again,everything is work right,
in my main.cpp,here is the code copy from the example in :http://doc.qt.io/archives/qt-4.8/signalsandslots.html#signals-and-slots
Counter a,b;
QObject::connect(&a, SIGNAL(valueChanged(int)),
&b, SLOT(setValue(int)));
a.setValue(12);
cout << "1" + string("a的值") + to_string(a.value()) + " b的值" + to_string(b.value()) << endl;
b.setValue(48);
cout << "2" + string("a的值") + to_string(a.value()) + " b的值" + to_string(b.value()) << endl;
after delete the "moc" files in "-Deubg" directory,I run the project again,I can still get right answer,what dose the "moc" files do,and when I need Generating "moc" files,and when should I add the Generating "moc" files to my project to use them?
in my another qt project,when I run the project,it shows me error"QMetaObject::connectSlotsByName: No matching signal for "
is it because I lack the "moc" files?thanks a lot!
-
moc files are generated by moc tool (Meta Object Compiler) - they are always generated for all QObject classes. They are absolutely required for meta stuff to work, so things like:
- signals
- slots
- Q_INVOKABLE
- QMeta* classes
However, these files are generated at build time. You don't need to keep them in your project, same as you don't need to store Makefiles, object files etc.
Actually, I strongly recommend building your code outside of your source code directory. Qt Creator does this automatically (it's called a "shadow build").Other code generators in Qt include:
- uic (generates UI headers from .ui files)
- rcc (generates cpp resource files from .qrc files)
- lupdate/lrelease (for translations)
-
I create a new qt project in Mac qt for test the example in :http://doc.qt.io/archives/qt-4.8/signalsandslots.html#signals-and-slots
for test the 'Signals & Slots', it seem it will generated moc_counter.cpp.o,moc_predefs.h,moc_counter.o "moc" files in the "-Deubg" directory after build,I delete the "moc" files,and I run the project again,everything is work right,
in my main.cpp,here is the code copy from the example in :http://doc.qt.io/archives/qt-4.8/signalsandslots.html#signals-and-slots
Counter a,b;
QObject::connect(&a, SIGNAL(valueChanged(int)),
&b, SLOT(setValue(int)));
a.setValue(12);
cout << "1" + string("a的值") + to_string(a.value()) + " b的值" + to_string(b.value()) << endl;
b.setValue(48);
cout << "2" + string("a的值") + to_string(a.value()) + " b的值" + to_string(b.value()) << endl;
after delete the "moc" files in "-Deubg" directory,I run the project again,I can still get right answer,what dose the "moc" files do,and when I need Generating "moc" files,and when should I add the Generating "moc" files to my project to use them?
in my another qt project,when I run the project,it shows me error"QMetaObject::connectSlotsByName: No matching signal for "
is it because I lack the "moc" files?thanks a lot!
@Princein
the moc files are generated automatically here are a couple of documents links so you can read about them.
http://doc.qt.io/archives/qt-4.8/moc.html
http://doc.qt.io/qt-5/why-moc.html -
moc files are generated by moc tool (Meta Object Compiler) - they are always generated for all QObject classes. They are absolutely required for meta stuff to work, so things like:
- signals
- slots
- Q_INVOKABLE
- QMeta* classes
However, these files are generated at build time. You don't need to keep them in your project, same as you don't need to store Makefiles, object files etc.
Actually, I strongly recommend building your code outside of your source code directory. Qt Creator does this automatically (it's called a "shadow build").Other code generators in Qt include:
- uic (generates UI headers from .ui files)
- rcc (generates cpp resource files from .qrc files)
- lupdate/lrelease (for translations)
@sierdzio said in when should Generating "moc" files in qt project,and what is the "moc" files's function？:
moc files are generated by moc tool (Meta Object Compiler) - they are always generated for all QObject classes. They are absolutely required for meta stuff to work, so things like:
signals
slots
Q_INVOKABLE
QMeta* classesHowever, these files are generated at build time. You don't need to keep them in your project, same as you don't need to store Makefiles, object files etc.
Actually, I strongly recommend building your code outside of your source code directory. Qt Creator does this automatically (it's called a "shadow build").
Other code generators in Qt include:uic (generates UI headers from .ui files)
rcc (generates cpp resource files from .qrc files)
lupdate/lrelease (for translations)thank you very much!
