Reinterpret_cast sent data - c++

Question

The code below is just an example.
Function1 is a dllexport, how do I properly convert/read the value of data inside of Foo2?
When I print the value, it returns 000001DFA1C501F3.
Function1(PVOID InPassThruBuffer, ULONG InPassThruSize);
void Foo(std::wstring* data) {
Function1(&data, sizeof(wchar_t))
}
// ==============================================
typedef struct _REMOTE_ENTRY_INFO_
{
UCHAR* UserData;
ULONG UserDataSize;
}REMOTE_ENTRY_INFO;
void __stdcall Foo2(REMOTE_ENTRY_INFO* inRemoteInfo)
{
std::wstring wdata;
if (inRemoteInfo->UserDataSize == sizeof(wchar_t))
wdata = reinterpret_cast<wchar_t *>(inRemoteInfo->UserData);
}

Answer 1

Try something more like this instead:
void Foo(std::wstring* data)
{
Function1(const_cast<wchar_t*>(data->c_str()), data->size() * sizeof(wchar_t));
// or, in C++17 and later:
// Function1(data->data(), data->size() * sizeof(wchar_t));
}
void __stdcall Foo2(REMOTE_ENTRY_INFO* inRemoteInfo)
{
wchar_t *wdata = reinterpret_cast<wchar_t*>(inRemoteInfo->UserData);
int wdatalen = inRemoteInfo->UserDataSize / sizeof(wchar_t);
}
Or, if Foo2() in called in the context of Function1() before Foo() exits, then you can just pass the std::wstring* pointer itself instead:
void Foo(std::wstring* data)
{
Function1(&data, sizeof(data));
// or, if Function1() does not *copy* the data,
// merely passes around the provided pointer as-is:
//
// Function1(data, sizeof(*data));
}
void __stdcall Foo2(REMOTE_ENTRY_INFO* inRemoteInfo)
{
std::wstring *wdata = *reinterpret_cast<std::wstring**>(inRemoteInfo->UserData);
// or:
// std::wstring *wdata = reinterpret_cast<std::wstring*>(inRemoteInfo->UserData);
}