The RtlAppendUnicodeStringToString routine concatenates two Unicode strings.
NTSTATUS
RtlAppendUnicodeStringToString(
IN OUT PUNICODE_STRING Destination,
IN PUNICODE_STRING Source
);
RtlAppendUnicodeStringToString can return one of the following:
Declared in wdm.h and ntddk.h. Include wdm.h or ntddk.h.
RtlAppendUnicodeStringToString copies bytes from the source up to the length of the destination buffer.
The Destination and Source buffers must be resident if the caller is running at IRQL >= DISPATCH_LEVEL.