编译我的程序时，在系统更新后来自QBrush的突然memcopy警告

Question

我不知道为什么会发生这种事。但每次我使用我安装的几个Qt版本编译我的应用程序时，我都会收到以下警告：

In file included from /home/Qt5.9.2/5.9.2/gcc_64/include/QtGui/qbrush.h:50,
                 from /home/Qt5.9.2/5.9.2/gcc_64/include/QtGui/qpalette.h:46,
                 from /home/Qt5.9.2/5.9.2/gcc_64/include/QtWidgets/qwidget.h:48,
                 from /home/Qt5.9.2/5.9.2/gcc_64/include/QtWidgets/qdesktopwidget.h:44,
                 from /home/Qt5.9.2/5.9.2/gcc_64/include/QtWidgets/QDesktopWidget:1,
                 from ../src/../../CommonClasses/SQLConn/../../CommonClasses/common.h:6,
                 from ../src/../../CommonClasses/SQLConn/dbinterface.h:10,
                 from ../src/../../EyeExperimenter/src/sslclient/sslclient.h:10,
                 from ../src/../../EyeExperimenter/src/sslclient/ssldbclient.h:4,
                 from ../src/sslwrapper.h:6,
                 from ../src/main.cpp:3:
/home/Qt5.9.2/5.9.2/gcc_64/include/QtGui/qtransform.h: In member function ‘QTransform& QTransform::operator=(QTransform&&)’:
/home/Qt5.9.2/5.9.2/gcc_64/include/QtGui/qtransform.h:81:46: warning: ‘void* memcpy(void*, const void*, size_t)’ writing to an object of type ‘class QTransform’ with no trivial copy-assignment; use copy-assignment or copy-initialization instead [-Wclass-memaccess]
     { memcpy(this, &other, sizeof(QTransform)); return *this; }
                                              ^
/home/Qt5.9.2/5.9.2/gcc_64/include/QtGui/qtransform.h:57:20: note: ‘class QTransform’ declared here
 class Q_GUI_EXPORT QTransform

谁能告诉我这个警告是什么，更重要的是，我如何摆脱它？根据我所看到的，它与我的系统当前使用的gcc8有关，但是我尝试在QtCreator的Qt工具包配置中更改编译器，但仍然出现警告...

Answer 1

您可以使用qmake作为构建系统生成器，然后使用gnu make来实际构建内容- Qt Creator只是在命令行中键入所有内容的快捷方式:)

您可以将相关标志传递给编译器，方法是将以下内容添加到.pro文件中，然后在项目上重新运行qmake (例如，删除build文件夹并再次构建)：

QMAKE_CFLAGS_WARN_ON += -Wno-class-memaccess
QMAKE_CXXFLAGS_WARN_ON += -Wno-class-memaccess
QMAKE_CFLAGS += -Wno-class-memaccess
QMAKE_CXXFLAGS += -Wno-class-memaccess