'TTabControl' cannot start a parameter declaration Full parser context，接口出错！解决思

'TTabControl' cannot start a parameter declaration Full parser context，接口出错！
5.H 文件代码
（错误就在）这句extern void sss(TTabControl *Sender);

C/C++ code

//---------------------------------------#ifndef Unit5H#define Unit5H//---------------------------------------extern void sss(TTabControl *Sender);#endif

5.CPP文件代码

C/C++ code

//---------------------------------------#pragma hdrstop#include "Unit5.h"//---------------------------------------#pragma package(smart_init)void sss(TTabControl *Sender){     TButton *newbtn=new TButton(Sender);     newbtn->Parent = Sender;}

错误信息
Checking project dependencies...
Compiling Project1.cbproj (Debug configuration)
[BCC32 Error] Unit5.h(7): E2147 'TTabControl' cannot start a parameter declaration
  Full parser context
  Unit5.cpp(5): #include Unit5.h
Failed
Elapsed time: 00:00:00.8


我接口这么写，出错了！希望前辈们给小弟一点指点！

[解决办法]
在Unit5.h文件中包含一个头文件。

C/C++ code

#ifndef Unit5H#define Unit5H#include <ComCtrls.hpp>//---------------------------------------extern void sss(TTabControl *Sender);#endif