Why QDoc don't work, it's really confusing.

[Stephen INF]

@mrjj
I tried,QDoc works well with qml ,but C++ Class still do not works.
I found generate documentation for qml only need one "source" file,but C++ class need both "source" and "header" file.
I guess there might be something wrong with header file ?So QDoc can't analyse source file as normal.

New C++ class "WidgetTest" added in project privided in the link.

header file:

#include <QWidget>

class WidgetTest : public QWidget
{
    Q_OBJECT
public:
    explicit WidgetTest(QWidget *parent = nullptr);
};

source file without "\fn":

/*!
  \class WidgetTest
  \brief WidgetTest for ui interface.
  \inmodule module0
*/

/*!
  WidgetTest::WidgetTest(QWidget *parent)

  constructor WidgetTest
*/
WidgetTest::WidgetTest(QWidget *parent) : QWidget(parent)
{

}

output:

warning: Cannot tie this documentation to anything
    [qdoc found a /*! ... */ comment, but there was no topic command (e.g., '\fn', '\page') in the comment and no function definition following the comment.]

source file with "\fn":

/*!
  \class WidgetTest
  \brief WidgetTest for ui interface.
  \inmodule module0
*/

/*!
  \fn WidgetTest::WidgetTest(QWidget *parent)

  constructor WidgetTest
*/
WidgetTest::WidgetTest(QWidget *parent) : QWidget(parent)
{

}

output:

warning: clang found diagnostics parsing \fn WidgetTest::WidgetTest(QWidget *parent)
    error: use of undeclared identifier 'WidgetTest'
    error: unknown type name 'QWidget'

widgettest.html is same:

[mrjj]

Hi
Did you change config file to match ?
sample uses

headers.fileextensions = "*.hpp"
but often its actually just "*.h"

[Stephen INF]

@mrjj
Yes，I changed that.

[mrjj]

@Stephen-INF
hmm odd. then
it seems clang have issue parsing the header
( QDoc uses clang from Qt 5.11)

You did follow step to install it ?
https://doc.qt.io/qt-5/qdoc-guide-clang.html

[Stephen INF]

@mrjj
Yes，I did it
installed LLVM6.0.1 and specify Clang location by "set LLVM_INSTALL_DIR=C:\Program Files\LLVM"

[mrjj]

@Stephen-INF
That seems pretty ok.
However, since the other part of generation seems to work, then
it must be something with clang and /fn
But I cant guess what not right.

[Stephen INF]

@mrjj
Well,can you try to generate C++ documentation with QDoc if you are free?

[mrjj]

@Stephen-INF
I might :)

[FrancoF]

@mrjj
Hi, I have a very simila problem.

[mrjj]

@FrancoF
Hi
I did try the QDoc but could not get any /fn to work either.

What version of Qt are you using ?

[DevMachines]

Re: [Why QDoc don't work](it's really confusing.)
I have the same issue with Qt5.12.0 on Windows. Does anyone have the solution for this?
Some notes - the enumerator was processed without problems:

class MyClass
{
public:
enum Type
{
}
void foo();
}

/*!
\enum MyClass::Type - parsed without errors
\value …
*/

/*!
\fn void MyClass::foo() - error: use of undeclared identifier 'MyClass' why???
*/

[DevMachines]

To fix the error, you need to switch to VS2015 Build Tool. For VS2017 I could not get the compiler to work. But for 2015 everything works as expected.

[Michael Scopchanov]

Check out this: https://stackoverflow.com/questions/52739030/why-does-q-object-break-qdoc

[FrancoF]

@mrjj
Qt 5.12.4 (GCC 9.1.0, 64 bit) installed on MSYS.