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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 following services are currently implemented in the Clang
code model plugin:
\list
\li Code completion
\li Syntactic and semantic highlighting
\li Diagnostics
\li Tooltips
\li Clang-Tidy and Clazy checks
\li Renaming of local symbols
\endlist
To use the plugin, you must activate it and configure it in \QC.
\section1 Using Clang-Tidy and Clazy
\l{https://clang.llvm.org/extra/clang-tidy/}{Clang-Tidy} and
\l{https://github.com/KDE/clazy/blob/master/README.md}{Clazy} are delivered
as parts of the Clang library delivered with \QC.
Clang-Tidy provides an extensible framework for diagnosing and fixing
typical programming errors, such as style violations, interface misuse, or
issues that can be found via static analysis.
Clazy 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.
\section1 Activating Clang Code Model
If you build \QC yourself, ensure that the plugin is also built, as
described in the \QC
\l{https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/README.md}{README file}.
To activate the plugin:
\list 1
\li Select \uicontrol Help > \uicontrol {About Plugins} >
\uicontrol {C++} > \uicontrol ClangCodeModel to enable the plugin.
\li Restart \QC to be able to use the plugin.
If you build \QC yourself, add \c ${LLVM_INSTALL_DIR}\bin to the
\c PATH variable so the LLVM libraries will be found on startup.
\endlist
\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 the \uicontrol {Clang Code Model Warnings} group, configure the
diagnostics that Clang should issue.
\list
\li In the \uicontrol {Configuration to use} list, select one of
the predefined configurations, or select \uicontrol Copy to
create a copy of a configuration and edit it to fit your
needs.
\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.
\li In the \uicontrol {Clang Plugins} field, select the Clang-Tidy and
Clazy checks to perform.
\endlist
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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