模板类中函数参数传值与传址问题! 请高手解决 谢谢
我做了一个通用线程类代码如下:#pragma once
template <class Type>
class BaseThread
{
private:
static unsigned int __stdcall StaticRun(void *pParam);
public:
HANDLE run(Type paras);
virtual int threadExc(Type para)=0;
BaseThread(void);
~BaseThread(void);
};
template <class Type>
BaseThread<Type>::BaseThread(void)
{
}
BaseThread<Type>::~BaseThread(void)
{
}
template <class Type>
HANDLE BaseThread<Type>::run( Type para){
unsigned threadID;
ThreadInfo<Type> *mParas=new ThreadInfo<Type>;
mParas->para1=para;
mParas->para2=this;
HANDLE handle=(HANDLE)_beginthreadex(0, 0, StaticRun ,(void*)mParas, 0, &threadID);
return handle;
}
template <class Type>
unsigned int BaseThread<Type>::StaticRun(void *pParam){
ThreadInfo<Type> *tParas=(ThreadInfo<Type>*)pParam;
BaseThread* baseThread=(BaseThread*)tParas->para2;
baseThread->threadExc(tParas->para1);
delete tParas;
_endthreadex(0);
return 0;
}
template <class Type>
结构体如下:
struct ThreadInfo
{
T para1;
void *para2;
};
// testThread 继承BaseThread
template <class Type>
class testThread :
public BaseThread <Type>
{
public:
testThread(void);
~testThread(void);
//int threadExc(const void *paras);
int threadExc(Type para);
};
template <class Type>
testThread<Type> ::testThread()
{
}
template <class Type>
testThread<Type>::~testThread(void)
{
}
template <class Type>
int testThread<Type>::threadExc(Type para){
char* value=para;
cout<<value;
return 0;
}
-------------------
main(){
testThread<char*>test; //testThread是BaseThread的子类,重载了threadExc方法
char *para="china";
HANDLE handle=test.run(para);
strcpy(para,"usa");
WaitForSingleObject(handle,INFINITE);
}
打印结果是:
usa
请问我如何打印出china;
模板参数自动变成对地址的操作.
如果参数改成传值.下面的代码是正确的.
testThread<int>test; //testThread是BaseThread的子类,重载了threadExc方法
int i=12;
HANDLE handle=test.run(i);
i=99;
将上边的threadExc方法改为:
int testThread<Type>::threadExc(Type para){
int value=para;
cout<<value;
return 0;
}
那么打印出的是12;
}
--------------------编程问答-------------------- 你将参数换成string类型的吧
因为你之前的写法传递的只是一个指针,指针内容可以被改写的.
用string的话就是具体的传递了一个string对象过去,这个对象包含了你所需要的字符串,
补充：.NET技术 , VC.NET
