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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Creator documentation.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
**
****************************************************************************/
// **********************************************************************
// NOTE: the sections are not ordered by their logical order to avoid
// reshuffling the file each time the index order changes (i.e., often).
// Run the fixnavi.pl script to adjust the links to the index order.
// **********************************************************************
/*!
\contentspage {Qt Creator Manual}
\previouspage creator-diff-editor.html
\page creator-clang-codemodel.html
\nextpage creator-finding-overview.html
\title Parsing C++ Files with the Clang Code Model
The \e {code model} is the part of an IDE that understands the language you
are using to write your application. It is the framework that allows \QC
to provide the following services:
\list
\li \l{Completing Code}{Code completion}
\li Syntactic and \l{Semantic Highlighting}{semantic highlighting}
\li Navigating in the code by using the \l{Searching with the Locator}
{locator}, \l{Moving to Symbol Definition or Declaration}
{following symbols}, and so on
\li Inspecting code by using the \l{Browsing Project Contents}
{class browser}, the \l{Viewing QML Types}{outline}, and so on
\li Diagnostics and \l{Viewing Function Tooltips}{tooltips}
\li \l{Finding Symbols}{Finding and renaming symbols}
\li \l{Applying Refactoring Actions}{Refactoring actions}
\endlist
\QC comes with a plugin that provides some of these services
for C++ on top of \l{http://clang.llvm.org/}{Clang}.
\section1 About the Clang Code Model
The Clang project provides libraries for parsing
C language family source files. The feedback you get through warning and
error markers is the same as a compiler will give you, not an incomplete
set or a close approximation, as when using the built-in \QC code model.
Clang focuses on detailed information for diagnostics, which is really
useful if the code contains typos, for example.
Clang keeps up with the development of the C++ language. At the time of this
writing, it supports C++98/03, C++11, C++14, C++17, C89, C99, Objective-C,
and Objective-C++.
On the downside, for large projects using Clang as code model is slower than
using the built-in code model. Clang does not need to generate object files,
but it still needs to parse and analyze the source files. For small projects
that only use STL, this is relatively fast. But for larger projects that
include several files, processing a single file and all the included files
can take a while.
The Clang code model plugin replaces services of the old C/C++ code model.
Currently the following services are implemented:
\list
\li Code completion
\li Syntactic and semantic highlighting
\li Diagnostics
\li Clang-Tidy checks
\li Clazy checks
\li Tooltips
\li Renaming of local symbols
\endlist
\section1 Code Model Warnings
The predefined configurations request Clang warnings at the following
levels:
\list
\li \uicontrol {Pedantic Warnings} uses the \c -Wpendantic option that
requests all the warnings demanded by strict ISO C and ISO C++.
\li \uicontrol {Warnings for Questionable Constructs} combines the
\c -Wall and \c -Wextra options to request all warnings about easily
avoidable questionable constructions and some additional warnings.
\li \uicontrol {Warnings for Almost Everything} uses the \c -Weverything
option with negative options to suppress some warnings.
\endlist
You can edit the predefined configurations to request specific warnings
beginning with \c -W. Each of these warnings also has a negative version
that begins with \c -Wno.
Keep in mind that some options turn on other options. For more information,
see \l{https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html}
{Options to Request or Suppress Warnings} or the GCC or Clang manual pages.
\section1 Using Clang-Tidy Checks
\l{https://clang.llvm.org/extra/clang-tidy/}{Clang-Tidy} is delivered
as a part of the Clang library delivered with \QC. It provides diagnostics
and fixes for typical programming errors, such as style violations,
interface misuse, or issues that can be found via static analysis.
\QC integrates the fixes and diagnostics into the Clang library, and
therefore they cannot be easily changed or extended when used with \QC.
\section1 Using Clazy
\l{https://github.com/KDE/clazy/blob/master/README.md}{Clazy} is delivered
as a part of the Clang library delivered with \QC. It helps Clang understand
Qt semantics. It prints out Qt related compiler warnings, ranging from
unnecessary memory allocation to misuse of API and provides refactoring
actions for fixing some of the issues.
The Clazy checks are divided into levels from 0 to 3. Each level adds checks
to the previous level. The checks at level 0 are very stable and provide
hardly any false positives, while the checks at level 3 can be considered
experimental.
For more information about the checks run at each level, see
\l{https://github.com/KDE/clazy/blob/master/README.md#list-of-checks}
{List of Checks} in the Clazy documentation.
\section1 Configuring Clang Code Model
To specify settings for the Clang code model:
\list 1
\li Select \uicontrol Tools > \uicontrol Options > \uicontrol C++ >
\uicontrol {Code Model}.
\image qtcreator-clang-code-model-options.png
\li To instruct the code model to interpret ambiguous header files as C
language files if you develop mainly using C, select the
\uicontrol {Interpret ambiguous headers as C headers} check box.
\li To process precompiled headers, deselect the
\uicontrol {Ignore precompiled headers} check box.
\li To avoid out-of-memory crashes caused by indexing huge source files
that are typically auto-generated by scripts or code, the size of
files to index is limited to 5MB by default. To adjust the limit,
edit the value for the \uicontrol {Do not index files greater than}
check box. To index all files, deselect the check box.
\li In \uicontrol {Clang Dianostics}, select one of the predefined
configurations, or select \uicontrol Copy to create a copy of a
configuration and edit it to fit your needs.
\list
\li In the \uicontrol Clang tab, edit the predefined
configuration to request specific warnings.
\li In the \uicontrol {Clang-Tidy} tab, select the checks to
perform.
\image qtcreator-clang-tidy.png
\li In the \uicontrol Clazy tab, select the level of Clazy
checks to perform.
\image qtcreator-clazy.png
\endlist
\endlist
\section1 Specifying Clang Settings at Project Level
You can specify Clang settings at project level in the build settings of
the project by selecting \uicontrol Projects >
\uicontrol {Clang Code Model}. In addition to configuring the diagnostics,
you can select the \uicontrol {Enable MSVC-compliant template parsing} check
box to parse templates in a MSVC-compliant way. This enables Clang to parse
headers for example from Active Template Library (ATL) or Windows Runtime
Library (WRL). However, using the relaxed and extended rules means that no
highlighting or completion can be provided within template functions.
\image qtcreator-clang-code-model-build-settings.png
*/
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