C++在派生类中调用基类的模板方法

Question

我在 cygwin 中使用 gcc 4.8.2 进行编译，编译完成时没有出现错误。但是当链接时，我收到以下消息:

bin/libUsersMgmnt.a(CUsersMgmnt.cpp.o): In function nsUserMgmnt::CUsersMgmnt::CUsersMgmnt()':
/home/HCAST2/v1.05-dev/UsersMgmnt/CUsersMgmnt.cpp:23: undefined
reference toint nsMsgHandler::CMsgHandler::createLocationUserMap()' /home/HCAST2/v1.05-dev/UsersMgmnt/CUsersMgmnt.cpp:23:(.text+0x19f): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `int nsMsgHandler::CMsgHandler::createLocationUserMap()' collect2: error: ld returned 1 exit status

我有这个基类:

Header File CMsgHandler.h

namespace nsMsgHandler
{
    class CMsgHandler
    {
    protected:
        template<class enhFlags> createLocationUserMap();
    };
}

代码文件CMsgHandler.cpp

... some code
using namespace nsMsgHandler;
... some code
template <class enhFlags>
int CMsgHandler::createLocationUserMap()
{
.....
}

这是派生类: 头文件CUsersMgmnt.h

namespace nsUserMgmnt
{
    class CUsersMgmnt : public CMsgHandler
    {
    public:
        CUsersMgmnt();
    };
}

代码文件CUsersMgmnt.cpp

... some code
using namespace nsUserMgmnt;
... some code
CUsersMgmnt::CUsersMgmnt()
{
    this->createLocationUserMap<nsUserMgmnt::types::Class1>();
}

我很确定代码中有错误。我试图解决这个问题几个小时。

Answer 1

你应该移动你的:

template <class enhFlags>
int CMsgHandler::createLocationUserMap()
{
.....
}

到CMsgHandler.h

否则编译器无法在 CUsersMgmnt.cpp 中实例化您的模板