The LPWSTR type is a 32-bit pointer to a string of 16-bit Unicode characters, which MAY be null-terminated. The LPWSTR type specifies a pointer to a sequence of Unicode characters, which MAY be terminated by a null character (usually referred to as "null-terminated Unicode").
In some protocols, an acceptable option is to not terminate a sequence of Unicode characters with a null character. Where this option applies, it is indicated in the protocol specification. In this situation, the LPWSTR or PWSTR type MUST either be tagged with the IDL modifier [string], which indicates string semantics, or MUST be accompanied by an explicit length specifier, as specified in the RPC_UNICODE_STRING (section 2.3.10) structure.
This type is declared as follows:
typedef wchar_t* LPWSTR, *PWSTR;