综合域15_释放内存不当引起内存错误.doc

7 试题
 某WIN32程序中采用了动态引用DLL中函数 (函数名foo)，但是系统经常提示非法操作内存错误，请问下面哪种方法是正确的不会出错,不必考虑内存泄漏    (正确答案D)
(A)
 动态库链接静态C运行库 代码为
void foo(string & strOut)
{
 strOut = "xxxxxxxxxxxxxxxxxxxxxxxx";
}
EXE链接动态C运行库  代码为
HMODULE h = LoadLibrary("xxx.dll");
LIBFUNC theFunc = GetProcAddress(h," foo"); 
string strContent;
(*theFunc) (strContent);
cout << strContent << endl;

(B)   
动态库链接静态C运行库 代码为
void foo(string & str)
{
 str = "xxxxxxxxxxxxxxxxxxxxxxxx";
}
 
EXE链接动态C运行库  代码为
HMODULE h = LoadLibrary("xxx.dll");
LIBFUNC theFunc = GetProcAddress(h," foo"); 
string  * pStrContent = new string;
(*theFunc) (* pStrContent);
 　cout << * pStrContent <      delete (pStrContent)； 

(C)
动态库链接静态C运行库 代码为
void foo(string & strOut)
{
 strOut = "xxxxxxxxxxxxxxxxxxxxxxxx";
}
并且DLL提供释放内存函数
void deleteFoo(string *pStrContent)
{
   if(pStrContent)
{
      delete pStrContent;
    }
}

EXE链接动态C运行库  代码为

HMODULE h = LoadLibrary("xxx.dll");
LIBFUNC theFunc = GetProcAddress(h," foo"); 
DEFFUNC delFunc = GetProcAddress(h," deleteFoo");
string  * pStrContent = new string;
(*theFunc)(* pStrContent);
 cout << * pStrContent <(*delFunc)( pStrContent);
 
(D) 动态库链接动态C运行库
 void foo(string & strOut)
{
    strOut = "xxxxxxxxxxxxxxxxxxxxxxxx";
}

EXE链接动态C运行库  代码为

HMODULE h = LoadLibrary("xxx.dll");
LIBFUNC theFunc = GetProcAddress(h," foo"); 
string strContent;
(*theFunc) (strContent);
cout << strContent << endl;