FAQ ⁽¹⁾ -- common compilation errors

MSVC

ComponentBase should be inherited AFTER QObject

Error message

>moc_Component.cpp(63): error C2039: 'staticMetaObject' : is not a member of 'pacpus::ComponentBase'
>          ComponentBase.h(60) : see declaration of 'pacpus::ComponentBase'
>moc_Component.cpp(80): error C2039: 'qt_metacast' : is not a member of 'pacpus::ComponentBase'
>          ComponentBase.h(60) : see declaration of 'pacpus::ComponentBase'
>moc_Component.cpp(85): error C2039: 'qt_metacall' : is not a member of 'pacpus::ComponentBase'
>          ComponentBase.h(60) : see declaration of 'pacpus::ComponentBase'

Solution

Your class declaration should look like:

class Component
    : QObject
    , ComponentBase
{
};

Class inheriting from QObject should be moc-ed

Error message

>Component.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const pacpus::Component::staticMetaObject" (?staticMetaObject@Component@pacpus@@2UQMetaObject@@B)
>Component.obj : error LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __thiscall pacpus::Component::metaObject(void)const " (?metaObject@Component@pacpus@@UBEPBUQMetaObject@@XZ)
>Component.obj : error LNK2001: unresolved external symbol "public: virtual void * __thiscall pacpus::Component::qt_metacast(char const *)" (?qt_metacast@Component@pacpus@@UAEPAXPBD@Z)
>Component.obj : error LNK2001: unresolved external symbol "public: virtual int __thiscall pacpus::Component::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@Component@pacpus@@UAEHW4Call@QMetaObject@@HPAPAX@Z)

Solution

• Check that you use moc tool on your class, i.e. file moc_Component.cpp is created and linked to the target.

1. Add Component.h to CMake variable MOC_FILES.
2. Add ${MOC_FILES} to the list of sources used by pacpus_add_library or pacpus_add_executable.

Varia

FAQ -- Frequently Asked Questions