UNICODE_STRING
When the ProcessInformationClass parameter is ProcessImageFileName, the buffer pointed to by the ProcessInformation parameter should be large enough to hold a UNICODE_STRING structure as well as the string itself. The string stored in the Buffer member is the name of the image file.
If the buffer is too small, the function fails with the STATUS_INFO_LENGTH_MISMATCH error code and the ReturnLength parameter is set to the required buffer size.