Add docs for qt_disable_unicode_defines()

Task-number: QTBUG-95712
Change-Id: I37a50d9e8a62c7d9c30014692d99ffe2eb9b90fb
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 9a7c552831a1117512b2827695af567c71aaf35c)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 53 insertions, 1 deletions

diff --git a/src/corelib/Qt6CoreMacros.cmake b/src/corelib/Qt6CoreMacros.cmake
index be2d6a20fb..f5ee8acf3f 100644
--- a/src/corelib/Qt6CoreMacros.cmake
+++ b/src/corelib/Qt6CoreMacros.cmake
@@ -2223,7 +2223,6 @@ properties of both types."
     endforeach()
 endfunction()
 
-# Disables the default unicode definitions for the target
 function(qt6_disable_unicode_defines target)
     set_target_properties(${target} PROPERTIES QT_NO_UNICODE_DEFINES TRUE)
 endfunction()
diff --git a/src/corelib/doc/src/cmake/qt_disable_unicode_defines.qdoc b/src/corelib/doc/src/cmake/qt_disable_unicode_defines.qdoc
new file mode 100644
index 0000000000..9f79af2f85
--- /dev/null
+++ b/src/corelib/doc/src/cmake/qt_disable_unicode_defines.qdoc
@@ -0,0 +1,53 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** 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.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+\page qt_disable_unicode_defines.html
+\ingroup cmake-macros-qtcore
+
+\title qt_disable_unicode_defines
+\target qt6_disable_unicode_defines
+
+\brief Prevents some unicode-related compiler definitions being set automatically on a target.
+
+\section1 Synopsis
+
+\badcode
+qt_disable_unicode_defines(target)
+\endcode
+
+\versionlessCMakeCommandsNote qt6_disable_unicode_defines()
+
+\section1 Description
+
+In Qt 6, the \c UNICODE and \c{_UNICODE} compiler definitions are set by
+default for targets that link against Qt modules. This is in line with the
+qmake behavior, but it is a change compared to the CMake API behavior in Qt 5.
+Calling \c{qt_disable_unicode_defines()} on a \c target prevents these compiler
+definitions from being automatically set.
+
+*/