QDoc may issue warnings when generating your documentation set. This section describes what these warnings mean and how to resolve them. This document does not describe warnings generated by Clang.
QDoc issues this warning when one part of the documentation (identified in the warning message) tries to refer to another, but doesn't correctly specify that other, the target of the link. This may arise because the reference to it is mistyped or because the target has changed name (for a function or type) or title (for another section).
Search the source code for that particular link target. If you get no results, gradually make the search less specific until you find a match.
If the link target looks like the name of a type or function, this could also be due to:
QDoc issues this warning if it is unable to find the file named after a \snippet or \quotefromfile command.
Some useful steps for correcting this:
exampledirs configuration variable in the *.qdocconf file. You may need to add an entry to this path, or correct an existing entry.QDoc issues this warning if it is unable to locate the snippet file quoted in a \snippet command.
For functions whose return-type is not void, QDoc checks if the return value is documented. This warning is issued if the documentation for a function or method doesn't contain a word starting with "return".
QDoc requires the documentation of a function or method to describe every parameter. It recognizes this by each parameter name (as specified where the function or method is declared in a header file) appearing after a \a command.
QDoc issues this warning when the parameter name given after an \a command does not match any of the parameters named in the header-file's declaration of the function or method being documented.
QDoc issues this warning when it sees a backslash, \, followed by a token it does not recognize as the name of a built-in command or a
user-defined macro. When quoting code that contains character escape sequences, you should enclose the code in \c{...} to prevent this warning against
the escape sequences.
When Clang parses a function statement after \fn, it checks this against the declaration in the header file. If Clang discovers discrepancies, it issues this warning message.
If you describe a QML type, you may specify the class it instantiates. Refer to the \instantiates command in the QDoc manual.
QDoc issues this warning if it failed to locate the documentation for the C++ class <ClassName>. Either the class is undocumented, it is marked \internal, or it originates from another documentation module and QDoc did not locate an index file for the corresponding dependency.
See also depends.
QDoc found a /*! ... */ comment, with no topic command, that was not immediately followed by a class, function or property definition. It thus does not know what the comment documents.
If a QDoc comment doesn't contain a topic command, QDoc does not know what the comment documents, and issues this warning. Very similar to Cannot tie this documentation to anything, but specific to comments that are not in C++ or QML files.
QDoc issues this warning when it finds two comments that document the same item. The location of the previously seen comment is provided in warning details.
For example, you see this warning when a function has a documentation comment preceding its definition, and a separate \fn comment elsewhere.
This warning means that a documentation set contains two comments containing \namespace commands with the same argument, <name>.
The documentation for <name> was found, but <name> is declared under a namespace that is either undocumented or QDoc was unable to locate the documentation for it.
This can be resolved by either documenting <namespace>, or if it is already documented in another module, ensure that this module has a dependency to it.
See also depends and {indexes-variable}{indexes}.
When parsing a \fn statement, Clang compares this with the function declaration in the header file. If the signature differs Clang issues this warning.
QDoc issues this warning if the QDoc comments do not relate a class, namespace, or headerfile to a module with the \inmodule command.
If the QDoc comment describes an entity that's not a member of some other entity (typically a namespace or class), it should use either \relates or \inmodule to associate it with its broader context. This warning is raised if it does not.
This means that QDoc cannot find a declaration of <name> in any header file, but has found a comment that claims to document it.
An example:
Cannot find 'Color::Red' specified with '\enum' in any header file.
A documentation comment claims to describe an enum, but QDoc didn't find a definition of that enum in a header file.
This may also be due to:
A parameter passed to \qmlproperty or \qmlmethod contains a combination of qmlModule::qmlType::identifier that is not defined anywhere.
Example:
Unrecognizable QML module/component qualifier for real QtQuick::DragHandler::DragAxis::minimum
DragHandler doesn't have a property called DragAxis.
A declaration of a \qmlproperty is missing its property type.
The \qmlproperty command expects to be followed by the property type, then the fully-qualified name of the property (i.e. the name ::-joined after the name of the class it belongs to).
Incorrect:
\qmlproperty MyWidget::count
Correct:
\qmlproperty int MyWidget::count
QDoc uses this warning when it finds two QDoc comments that document the same QML property, either by appearing just before its definition, or using the \qmlproperty command.
Example:
\qmlproperty real QtQuick.Controls::RangeSlider::first.value \qmlproperty real QtQuick.Controls::RangeSlider::first.position \qmlproperty real QtQuick.Controls::RangeSlider::first.visualPosition \qmlsignal void QtQuick.Controls::RangeSlider::first.moved() \qmlsignal void QtQuick.Controls::RangeSlider::second.moved()
Error message:
Command '\\qmlsignal' not allowed with QML/JS property commands
This warning is specific to property group documentation. QDoc allows multiple (qml|js)property or (qml|js)attachedproperty topic commands in a single documentation comment to document a property group where the last element in the path is <group>.<property>. Any other topic commands triggers this warning.
QDoc produces this warning if \reimp is used to document a method, as an override of a virtual method, when no base class has a virtual method with the given name and signature. This may happen because the method it was written to override has changed its signature, or is no longer virtual.
Qdoc tries to create a link to the function that this one reimplements, but it could not find the link target, likely because that function is not documented. This can also arise if no base class has a virtual method with this name and signature; which might arise due to a renaming, a change in signature or the base no longer declaring it virtual.
The \inherits command is used to document that a QMl type inherits some other QML type. This warning is issued if that other QML type is the same as the QML type documented.
Example:
\qmltype Foo \inherits Foo
The \instantiates command can only be used in a QDoc comment that documents a QML type.
When documenting QML property groups, all properties listed in the comment block must belong to the same QML type.
In the example's source directory, QDoc expects to find a project file named CMakeLists.txt, or a file with a .pro, .qmlproject, or .pyproject extension where the base name
matches that of the example directory. For example, examples/mymodule/helloworld/helloworld.pro.
QDoc issues this warning when one name is aliased to more than one command when reading the configuration.
The search path for <filename> is defined by the following variables in the .qdocconf file: sources, sourcedirs, and exampledirs.
QDoc failed to find a file named in a command (such as \quotefromfile, \snippet, \include) that tells it to retrieve content from the named file. It searches each directory named in the search path. If there is no file with this name in any of those directories, or the file is found but not readable, QDoc issues this warning. Check that the combination of search path and <filename> is correctly spelled, and that you have read permissions for the file.
Note: <filename> may include a directory name prefix; the whole <filename> is appended to each directory in the search path.
The \raw command and the corresponding \endraw command delimit a block of raw mark-up language code. The \raw command must be followed by the format name. For now, this can only be HTML.
A \macro that specifies an output format cannot also have a generic definition.
An example of a configuration that triggers this warning:
macro.gui = \b macro.gui.HTML = "<b>\1</b>"
When a QDoc comment uses a backslash followed by a token that is not a QDoc built-in command and has not been defined as a custom command using \alias or macro, QDoc produces this warning. Check the spelling of the command name and look to see if your QDoc configuration has neglected to include whatever would have defined it, if it is a custom command.
This may also be produced due to code being quoted in the QDoc comment, for example the author may have referred to the C string termination character '\0' or one of the other C string escape sequences such as
'\n' without escaping the backslash. Escape the backslash as \ to include a literal backslash in the documentation, or enclose the code fragment in \c{...}, which suppresses interpretation
of backslashes as introducing QDoc commands.
This means that there are two \target commands with the same parameter. They should be unique. This warning is followed by the warning "The previous occurrence is here".
QDoc failed to find an include file named in a command. QDoc searches each directory named in the search path. If there is no file with this name in any of those directories, or the file found in that search is not readable, QDoc issues this warning. Check that the combination of search path and <filename> is correctly spelled, and that you have read permissions for the file.
Note: <filename> may include a directory name prefix; the whole <filename> is appended to each directory in the search path.
This means QDoc cannot find the identifier <id> in the \include <file> or {snippet-command}{\snippet} <file>.
The snippet <tag> was found in the \snippet <file>, but it is empty.
This warning concerns formatting commands: bold, italic, index, link, span, subscript, superscript, teletype, uicontrol, underline. A formatting command cannot be used within the text it applies to. An example of this:
There is \b{no \b{super-}bold}.
\encode
\section1 Can't use <inner> in <outer>
This warning is issued for commands that cannot be nested.
Example:
\badcode
\list
\li \table
\row \li Hello \li Hi
\endtable
\endlist
Results in the QDoc warning "Can't use '\table' in '\list'".
Some examples:
This warning is issued if, for example, you have an \endlist without a preceding \list. It applies to all commands that come in pairs (e.g. startFoo/endFoo).
The titles listed for a \sa command should be separated from one another with commas.
QDoc is attempting to expand a macro, and expects that macro to have a default definition. Some macros may only have format-specific definitions.
Example:
macro.pi.HTML = "π" # encodes the pi symbol for HTML output format
There are however instances where macro expansion requires a format-independent macro. For example, you can have macros in section titles, but they must have default definitions.
The given macro needs more parameters than it was given. See the definition of the macro in the configuration for further details.
Points to a '(' without a corresponding ')', or vice versa.
Example:
Warning "No documentation for QNativeInterface."
QDoc detects the declaration of namespace QNativeInterface in a header file, but does not find a QDoc comment where that namespace has been documented.
Example:
Cannot find 'QSGMaterialRhiShader::RenderState::DirtyState' specified with \enum in any header file.
QDoc issues this warning when it finds a \value directive in an \enum comment that names a value not found in the header file that declared the enumerated type documented.
<enum list>'s \value or \omitvalue entries did not include one for <enum>, which is named in the declaration of <enum list> in the header file.
Example:
Failed to find index: path/to/QtCrator/appmanplugin/manual.index
In this case, it clearly means the indexes variable contains a typo in the path of the index file.
Incorrect:
indexes += path/to/QtCrator/appmanplugin/manual.index
Correct:
indexes += path/to/QtCreator/appmanplugin/manual.index
The command "\generatelist examplefiles" can only be used in example documentation (i.e., when the topic command is \example).
Below a short overview of all possible arguments for \generatelist:
QDoc issues this warning if you specify \generatelist <group> and the group does not contain any items, or if you specify \generatelist <group> <pattern> and no item in the group
matches the pattern.
This warning issues if the argument to \generatelist is a non-existing group.
Example:
\generatelist draganddrop
This statement generates a list of classes or QML types in the draganddrop group. Classes or QML types are added to the draganddrop group by the \l {ingroup-command}{\ingroup} draganddrop command in their
\class or \qmltype comment.
QDoc issues this warning message if no entity has this \ingroup draganddrop statement.
The search path to the image is wrong, or the image file does not exist.
This can have a variety of causes:
QDoc issues this warning if you document a QML type, but omit the \inqmlmodule command. Example:
Could not resolve QML import statement for type 'ItemSelectionModel' \encode Incorrect: \badcode \qmltype ItemSelectionModel \instantiates QItemSelectionModel \since 5.5 \ingroup qtquick-models
Correct:
\qmltype ItemSelectionModel \instantiates QItemSelectionModel \inqmlmodule QtQml.Models \since 5.5 \ingroup qtquick-models
The argument to the \brief command is a sentence, summarizing the topic documented, so should end in a full stop. It should also be brief.
QDoc issues this warning if it has been compiled without support for QML/JS parsing. This should not happen unless you have a custom build of QDoc.
Some QDoc commands take regular expressions as parameters. QDoc gives this warning when the text given as such a parameter is not a valid regular expression, usually due to it containing characters with special meanings in regular expressions, that should have been escaped.
Example:
notifications.qdoc:56: (qdoc) warning: Invalid regular expression '^})$'
\quotefromfile webenginewidgets/notifications/data/index.html \skipuntil resetPermission
Invalid regular expression:
\printuntil /^})$/
Valid regular expression:
\printuntil /^\}\)$/
The \printuntil command prints until it meets a line consisting of only a right curly brace followed by a right parenthesis. In this case, the curly brace and the parenthesis need to be escaped because they have special meanings in regular expressions.
Using <indexfile> as index file for dependency <depend>
Multiple -indexdir paths were passed to QDoc as command line options, and more than one contained an .index file that matches a dependency. QDoc picks the one with the latest timestamp
automatically.
Typically, this warning indicates that there are build artifacts left from a previous documentation build.
Example:
"QMake" Cannot locate index file for dependency "activeqt"
The documentation project QMake could not locate activeqt.index in any of the specified index directories. In this case, the specified index directories are specified in qmake.qdocconf.
QDoc expected to see one or more -indexdir arguments on the command line. Without them, QDoc cannot locate the index files of any dependencies defined with the 'depends' configuration variable.
QDoc issues this warning when it finds two comments that appear to describe the same entity. The location of the previously seen comment is provided in warning details.
\list can take an optional argument: a single number or character that modifies the list style. Refer to the {list-command}{\list} documentation for more details. If you use an argument that is not recognized, QDoc issues this warning.
QDoc comments can contain QML code. This code can be found in a snippet, or in the QDoc comments delimited by \qml and {endqml-command}{\endqml}.
Example:
If there is a syntax error in the QML code, QDoc issues the warning
Unable to parse QML snippet: Syntax error at line 97, column 42
Snippets can also contain QML and also there the code is checked. If there is for example a missing curly brace in the code, QDoc issues the warning
Unable to parse QML snippet: Expected token '{' at line 63, column 52
QDoc often fails to parse incomplete QML snippets; in these cases, it's often OK to replace the \qml ... \endqml commands with \code ... \endcode to suppress this warning.
Example:
Command "\snippet (//! [2]) failed at end of file qmlbars/qml/qmlbars/main.qml".
In this case the warning means that the \snippet command did not find a second label "//! [2]" to mark the end of the snippet. It could also mean that it didn't find any occurrence of that snippet tag in this snippet file.
Another example:
Command '\skipto' failed at end of file 'styling/CMakeLists.txt".
The \skipto + <pattern> moves the cursor to the next line containing that pattern. If \skipto doesn't find it, QDoc issues this warning.
This warning clearly means it cannot open a file for writing, probably because of a wrong path, or permission to write in a certain directory.
The \title command sets the title for a page.
\page activeqt-server.html \title Building ActiveX servers in Qt
QDoc issues this warning if a certain title is used in more than one page.
QDoc uses a fixed-size buffer when tokenizing source files. If any single token in the file has more characters than the maximum limit, QDoc issues this warning.
While QDoc continues parsing the file, only the part of the token that fits into the buffer is considered, meaning that the output might be mangled.
To resolve this warning, the relevant content must be reduced in size, either by splitting it, if possible, or by removing some of its parts.
The maximum amount of characters for a single token is shown alongside the warning, for example:
file.qdoc:71154: (qdoc) warning: The content is too long. [The maximum amount of characters for this content is 524288. Consider splitting it or reducing its size.]
Note: Since content that is too long is not parsed in full, QDoc may issue warnings that are false positives. Resolve all warnings of this type before fixing other warnings.
See also Cannot find qdoc include file <filename> and Cannot open file to quote from: <filename>.
