VS2013的Qt4到Qt5迁移链接程序警告（和错误）

Question

我有一个项目，最初是使用Qt4开发的，现在正在迁移到Qt5。 经过几个小时的重新处理一些代码并删除了新近弃用的调用，我得以使项目得以编译，但是现在我很难将其链接。

我正在使用CMake生成项目文件。 我首先通过修改“解决方案”的CMake文件并替换以下内容开始迁移：

#############################################
# find QT
FIND_PACKAGE(Qt4 REQUIRED)

# configure QT modules
SET(QT_USER_QTCORE TRUE)
SET(QT_USE_QTMAIN TRUE)
SET(QT_USE_QTWEBKIT TRUE)
SET(QT_USE_QTNETWORK TRUE)
SET(QT_USE_QTSQL TRUE)

SET(QT_USE_QTXML TRUE)
SET(QT_USE_QTUITOOLS TRUE)

# include QT requirements
INCLUDE(${QT_USE_FILE})
ADD_DEFINITIONS(${QT_DEFINITIONS})
#############################################

与（这需要清理）

#############################################
# find QT
set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_AUTOMOC ON)

FIND_PACKAGE(Qt5Concurrent REQUIRED)
FIND_PACKAGE(Qt5Core REQUIRED)
FIND_PACKAGE(Qt5Network REQUIRED)
FIND_PACKAGE(Qt5Sql REQUIRED)
FIND_PACKAGE(Qt5WebKit REQUIRED)
FIND_PACKAGE(Qt5WebKitWidgets REQUIRED)
FIND_PACKAGE(Qt5Widgets REQUIRED)
FIND_PACKAGE(Qt5Xml REQUIRED)

INCLUDE_DIRECTORIES(
    ${Qt5Concurrent_INCLUDE_DIRS}
    ${QT5_FOLDER}
    "C:/Qt/Qt5.0.2/5.0.2/msvc2012_64/include"
)

ADD_DEFINITIONS(${QT_DEFINITIONS})
#############################################

此后，我注释掉了对ADD_SUBDIRECTORY()所有调用，并开始将它们一次添加回去。 我的项目使用Log4Qt，并且由于它对其他子目录没有其他依赖关系，因此这是我开始从事的第一个子项目。

在Log4Qt的CMakeLists.txt文件中，我只是将QT4_WRAP_CPP(MOC_SOURCE_FILES ${MOC_HEADERS})更改为QT5_WRAP_CPP(MOC_SOURCE_FILES ${MOC_HEADERS}) ，并将MOC_HEADERS定义为所有MOCQt头中的所有MOCQt头。

当我将其加载到VS2013中并进行构建时，它可以正常编译，但链接会为每个moc_ *发出相同的警告：

>moc_stringmatchfilter.obj : warning LNK4006: "public: static struct QMetaObject const Log4Qt::StringMatchFilter::staticMetaObject" (?staticMetaObject@StringMatchFilter@Log4Qt@@2UQMetaObject@@B) already defined in log4qt_automoc.obj; second definition ignored
>moc_stringmatchfilter.obj : warning LNK4006: "private: static void __cdecl Log4Qt::StringMatchFilter::qt_static_metacall(class QObject *,enum QMetaObject::Call,int,void * *)" (?qt_static_metacall@StringMatchFilter@Log4Qt@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z) already defined in log4qt_automoc.obj; second definition ignored
>moc_stringmatchfilter.obj : warning LNK4006: "public: virtual struct QMetaObject const * __cdecl Log4Qt::StringMatchFilter::metaObject(void)const " (?metaObject@StringMatchFilter@Log4Qt@@UEBAPEBUQMetaObject@@XZ) already defined in log4qt_automoc.obj; second definition ignored
>moc_stringmatchfilter.obj : warning LNK4006: "public: virtual void * __cdecl Log4Qt::StringMatchFilter::qt_metacast(char const *)" (?qt_metacast@StringMatchFilter@Log4Qt@@UEAAPEAXPEBD@Z) already defined in log4qt_automoc.obj; second definition ignored
>moc_stringmatchfilter.obj : warning LNK4006: "public: virtual int __cdecl Log4Qt::StringMatchFilter::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@StringMatchFilter@Log4Qt@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) already defined in log4qt_automoc.obj; second definition ignored
>moc_stringmatchfilter.obj : warning LNK4221: This object file does not define any previously undefined public symbols, so it will not be used by any link operation that consumes this library

我继续进行迁移，并继续收到相同的警告。 例如，这是子项目之一的完整CMakeLists.txt文件：

PROJECT（网络）

INCLUDE_DIRECTORIES（$ {} CMAKE_CURRENT_BINARY_DIR）

设置（SOURCE_FILES RequestCache.cpp WebClient.cpp）

设置（MOC_HEADERS RequestCache.h WebClient.h）

SET（HEADER_FILES $ {MOC_HEADERS}）

SET（DEPENDENCY_LIST log4qt Core）

ADD_LIBRARY（网络静态$ {SOURCE_FILES} $ {HEADER_FILES} $ {MOC_SOURCE_FILES}）

QT5_USE_MODULES（网络网络）

和（某些）警告：

moc_WebClient.obj : warning LNK4006: "public: virtual struct QMetaObject const * __cdecl owl::WebClient::metaObject(void)const " (?metaObject@WebClient@owl@@UEBAPEBUQMetaObject@@XZ) already defined in Network_automoc.obj; second definition ignored
moc_WebClient.obj : warning LNK4006: "public: virtual void * __cdecl owl::WebClient::qt_metacast(char const *)" (?qt_metacast@WebClient@owl@@UEAAPEAXPEBD@Z) already defined in Network_automoc.obj; second definition ignored
moc_WebClient.obj : warning LNK4006: "public: virtual int __cdecl owl::WebClient::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@WebClient@owl@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) already defined in Network_automoc.obj; second definition ignored
moc_WebClient.obj : warning LNK4006: "private: static void __cdecl owl::WebClient::qt_static_metacall(class QObject *,enum QMetaObject::Call,int,void * *)" (?qt_static_metacall@WebClient@owl@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z) already defined in Network_automoc.obj; second definition ignored
moc_WebClient.obj : warning LNK4006: "public: static struct QMetaObject const owl::WebClient::staticMetaObject" (?staticMetaObject@WebClient@owl@@2UQMetaObject@@B) already defined in Network_automoc.obj; second definition ignored
moc_WebClient.obj : warning LNK4221: This object file does not define any previously undefined public symbols, so it will not be used by any link operation that consumes this library

继续向前，我继续并添加了所有相关项目，并尝试构建该项目的可执行文件。 然后出现以下错误（可执行文件的项目名称为“ Owl”）（这是错误的摘录，而不是完整的清单）：

error LNK2005: "public: static struct QMetaObject const owl::PostListWebView::staticMetaObject" (?staticMetaObject@PostListWebView@owl@@2UQMetaObject@@B) already defined in moc_PostListView.obj   C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "private: static void __cdecl owl::PostListWebView::qt_static_metacall(class QObject *,enum QMetaObject::Call,int,void * *)" (?qt_static_metacall@PostListWebView@owl@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z) already defined in moc_PostListView.obj   C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "public: virtual struct QMetaObject const * __cdecl owl::BoardTreeView::metaObject(void)const " (?metaObject@BoardTreeView@owl@@UEBAPEBUQMetaObject@@XZ) already defined in moc_BoardTreeView.obj    C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "public: virtual void * __cdecl owl::BoardTreeView::qt_metacast(char const *)" (?qt_metacast@BoardTreeView@owl@@UEAAPEAXPEBD@Z) already defined in moc_BoardTreeView.obj C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "public: virtual int __cdecl owl::BoardTreeView::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@BoardTreeView@owl@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) already defined in moc_BoardTreeView.obj    C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "private: static void __cdecl owl::BoardTreeView::qt_static_metacall(class QObject *,enum QMetaObject::Call,int,void * *)" (?qt_static_metacall@BoardTreeView@owl@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z) already defined in moc_BoardTreeView.obj  C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "public: virtual struct QMetaObject const * __cdecl owl::ConfiguringBoardDlg::metaObject(void)const " (?metaObject@ConfiguringBoardDlg@owl@@UEBAPEBUQMetaObject@@XZ) already defined in moc_ConfiguringBoardDlg.obj  C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl
error LNK2005: "public: virtual void * __cdecl owl::ConfiguringBoardDlg::qt_metacast(char const *)" (?qt_metacast@ConfiguringBoardDlg@owl@@UEAAPEAXPEBD@Z) already defined in moc_ConfiguringBoardDlg.obj   C:\vbulletin\cmake\deltas\Win64\Deltas\Owl_automoc.obj  Owl

我究竟做错了什么？ 我必须在我的CMake文件中解决此问题吗？ 我看不到我如何错误地配置CMake还是缺少其他内容？

谢谢！

Answer 1

感觉您没有正确清理项目构建目录。 另外，如果您的CMake版本足够高，则可以尝试使用CMAKE_AUTOMOC 。 更多细节在这里 。