预期的'int'之前的unqualified-id [英] expected unqualified-id before ‘int’

问题描述

class A {
   public:
      virtual ~A() {};
      virtual int emit(int t, void* a)=0;
};

template <class dest_type="">
class B : public A {
   public:
      typedef int (dest_type::*classpfn)(int, void*);
      B(dest_type* pclass, classpfn pfn) : p(pclass), fn(pfn) {};
      virtual int emit(int t, void* a) { return (p->*fn)(t, a); }
   private:
      dest_type *p;
      classpfn fn;
};

输出:
=======
abc.h:222:错误:在'int'之前的预期unqualified-id
abc.h:222:错误:预期在'int'之前的')'

Output:
=======
abc.h:222: error: expected unqualified-id before ‘int’
abc.h:222: error: expected ‘)’ before ‘int’

推荐答案

这部分template<class dest_type="">，对我来说很奇怪，您是否要设置默认类型dest_type为空字符串吗?

尝试删除该内容，以使您离开template<class dest_type>.

希望这会有所帮助，
弗雷德里克(Fredrik)

This part template<class dest_type="">, looks weird to me, are you trying to set the default type dest_type to an empty string?

Try removing that so that you''re left with template<class dest_type>.

Hope this helps,
Fredrik

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