VC++中的_com_ptr_t赋值 [英] _com_ptr_t assignment in VC++
本文介绍了VC++中的_com_ptr_t赋值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有以下代码:
int _tmain(int argc, _TCHAR* argv[])
{
// Initialize COM.
HRESULT hr = CoInitialize(NULL);
// Create the interface pointer.
ICalculatorPtr pICalc(__uuidof(ManagedClass));
long lResult = 0;
// Call the Add method.
pICalc->Add(5, 10, &lResult);
wprintf(L"The result is %d\n", lResult);
// Uninitialize COM.
CoUninitialize();
return 0;
}
我想首先将 pICalc
声明为全局变量,然后在 _tmain
函数中分配一些值.我怎样才能做到这一点?我想,像这样:
I want to first declare pICalc
as a global variable and later assign some value inside the _tmain
function. How can I do that? I suppose, like this:
ICalculatorPtr pICalc;
//...
int _tmain(int argc, _TCHAR* argv[])
{
//...
pICalc = __uuidof(ManagedClass);
}
但这会抛出:
错误 C2679:二进制=":未找到采用const _GUID"类型的右侧操作数的运算符(或没有可接受的转换)
error C2679: binary '=' : no operator found which takes a right-hand operand of type 'const _GUID' (or there is no acceptable conversion)
提前致谢.
解决方案:
ICalculatorPtr pICalc = NULL;
//...
int _tmain(int argc, _TCHAR* argv[])
{
//...
pICalc = new ICalculatorPtr(__uuidof(ManagedClass));
}
推荐答案
您建议的解决方案会泄漏内存.做起来
Your suggested solution leaks memory. Make it
ICalculatorPtr pICalc;
pICalc.CreateInstance(__uuidof(ManagedClass));
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