qtmain 是帮助程序库，使开发者能够在 Windows 编写跨平台 main() 函数。若不使用
qmake
或其它构建工具，譬如：
CMake
，则需要链接到
qtmain
库。
应用程序静态链接 qtmain 库。要避免静态链接问题和 GNU 次一般公共许可 (LGPL) ，它被许可在商业许可下，和 BSD 3 条款新 (或修订) 许可 .
Copyright (C) 2016 The Qt Company Ltd.
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.
BSD License Usage
Alternatively, you may use this file under the terms of the BSD license
如下：
"Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of The Qt Company Ltd nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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