Question

I’m trying to make an RPC call which requests 2 numbers and a string from the RPC server, the IDL looks like this:

void GetCurrentStatus([in] handle_t hBinding, [out, ref] DWORD *dwRef1, [out, ref] DWORD *dwRef2, UINT *nLength, [out, size_is(, *nLength)] LPWSTR *pszName);

In the server-side call I do this:

// name = std::wstring
*pszName = (wchar_t*)midl_user_allocate(name.length()+1 * sizeof(wchar_t));
_tcscpy(*pszName, name.c_str());
*nLength = name.length();

But any attempt to call from the client-side results in nothing returned the error The array bounds are invalid.

What is the correct way to return a string from an RPC call?

Thanks,
J

Answer 1

If you have a choice in the matter, use BSTR (i.e. SysAllocString). RPC knows all about this data type and how to copy it and find its length.

Just

[out, retval] BSTR* pstrName

is enough, no separate length parameter needed.