qmake behavior

[Radek]

Thanks ChrisW67! This seems to work! I added "int trythis;" into a header, recompiled (not so long recompiling, not everything got rebuilt evidently), run debug and inspected the class. It contained "trythis" as it should do. My makefile now contains references to header files. It did not before.

[wysota]

Out of curiosity (I didn't get a response last time I indirectly asked about it) -- how exactly do you include statements look like? Do they use relative paths? I mean do they look like:

#include "../hpp/myframe.hpp"

#include "../hpp/myframe.hpp"

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or rather

#include "myframe.hpp" // or <myframe.hpp>

#include "myframe.hpp" // or <myframe.hpp>

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?

If DEPENDPATH helps then it is likely you are using the latter.

[Radek]

#include <myframe.hpp> with all my headers. That's why I have set INCLUDEPATH.

[wysota]

For that you need DEPENDPATH as well

See the docs (underlined by me):

This variable contains the list of all directories to look in to resolve dependencies. This will be used when crawling through included files.

INCLUDEPATH is only used for compilation (e.g. it makes no sense to make your app dependent of /usr/include/*, right?).

[starling13]

I don't wish to start new thread for this small question:

I have the source code tree of existing project, where every .cpp file for class, inherited from QObject, ends with inclusion of "class_name.moc" file.
I try to make the Qt project file to use with QtCreator for this sources.
The problem is in that qmake generates makefile, where *.cpp file depends on corresponding *.moc file, but the *,moc file rules only generated for *.cpp, wich declares private classes, inherited from QObject.

Is it possible to generate makefile with rules to make *.moc files for every *.cpp with *.moc inclusion?

Example:
class1.h

#include <qt4/QtCore/QObject>
class Class1 : public QObject
{
    Q_OBJECT
public:
    Class1();
};

#include <qt4/QtCore/QObject>
class Class1 : public QObject
{
    Q_OBJECT
public:
    Class1();
};

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class1.cpp

#include "class1.h"
 
Class1::Class1()
{
}
#include "class1.moc"

#include "class1.h"

Class1::Class1()
{
}
#include "class1.moc"

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class1.pro

TEMPLATE = lib
INCLUDEPATH += .
 
HEADERS += class1.h
SOURCES += class1.cpp

TEMPLATE = lib
INCLUDEPATH += .

HEADERS += class1.h
SOURCES += class1.cpp

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qmake
make
...
No rule to make target `class1.moc', needed by `class1.o'.

But if cpp will be modified:
class1.cpp

#include "class1.h"
 
class Private : public QObject
{
    Q_OBJECT
};
 
Class1::Class1()
{
}
 
#include "class1.moc"

#include "class1.h"

class Private : public QObject
{
    Q_OBJECT
};

Class1::Class1()
{
}

#include "class1.moc"

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then lib is generated correctly.

[Radek]

I have seen such #includes, too, but, luckily, I didn't need to compile it I am still a beginner but, IMO, the *.moc files are some relic of Qt3. In a Qt4 project, you do not create *.moc files. AFAIK, the *.moc files aren't a part of a Qt4 project directly: you find files like moc_class1.o in the compiled project but no class1.moc file.

I recommend checking whether the *.moc files contain something what should be in your *.cpp and *.hpp files. If they do then update the source files accordingly. If they don't (they contain only dependencies, includes and similar things) then comment all "#include something.moc" out, create a Qt4 project, add all sources and headers and compile. You should pass (if it is a Qt3 project, you might need the Qt3 support). The MOC info should be processed by qmake without your intervention.

[anda_skoa]

IMO, the *.moc files are some relic of Qt3.

No, they are just a different way of dealing with the code generated by MOC.

Without the include the behavior is to generate cpp files which are then compiled separately and linked like any other object file.

The alternative with the include is used in three scenarios:
1) when the Q_OBJECT using class declaration is inside the cpp file, not in a header
2) when the code generated by moc needs to see some declarations that are private to the cpp file
3) to speed up builds (no extra invocation of compiler for the moc generated file)

Not sure why it doesn't work for starling13 though.

Cheers,
_