Question

I have a com objects function having a C# return type of string

string getData();

In my C++ code I have

cpi->getData(); 

where cpi is a pointer to an instance of com object.

How do I get this returned data in a C++ variable?

—edit—

I also have another function called handlepacket(char* data).

How do I pass this cpi->getData returned string data to this function?

A C++ code piece will be very helpful.

Answer 1

The COM string type is BSTR. It has non-trivial memory-management rules. Luckily, the _bstr_t C++ class wraps BSTR and gives you reasonable semantics. So, _bstr_t foo = cpi->getData(); is the easiest way.

You can pass this string to a handlepacket(wchar_t* data). The COM string type is Unicode text, not 8 bits data. If your getData function returns 8 bits data, it should have returned an array of bytes.