Print a GUID variable

Use the StringFromCLSID function to convert it to a string

e.g.:

GUID guid;
CoCreateGuid(&guid);

OLECHAR* guidString;
StringFromCLSID(guid, &guidString);

// use guidString...

// ensure memory is freed
::CoTaskMemFree(guidString);

Also see the MSDN definition of a GUID for a description of data4, which is an array containing the last 8 bytes of the GUID