Windows Driver Kit: Kernel-Mode Driver Architecture
RtlUnicodeStringCat
The RtlUnicodeStringCat function concatenates two strings that are contained in UNICODE_STRING structures.
NTSTATUS
RtlUnicodeStringCat(
IN OUT PUNICODE_STRING DestinationString,
IN PCUNICODE_STRING SourceString
);
Parameters
- DestinationString
- A pointer to a UNICODE_STRING structure. This structure includes a buffer that, on input, contains a destination string to which the source string will be concatenated. On output, this buffer is the destination buffer that contains the entire resultant string. The source string is added to the end of the destination string. The maximum number of bytes in the structure's string buffer is NTSTRSAFE_UNICODE_STRING_MAX_CCH * sizeof(WCHAR).
- SourceString
- A pointer to a UNICODE_STRING structure. This structure includes a buffer that contains the source string. This string will be added to the end of the destination string. The maximum number of bytes in the structure's string buffer is NTSTRSAFE_UNICODE_STRING_MAX_CCH * sizeof(WCHAR).
Return Value
RtlUnicodeStringCat returns one of the following NTSTATUS values.
| Return value | Meaning |
|---|
| STATUS_SUCCESS | This success status means that source data was present, the strings were concatenated without truncation, and the resultant destination buffer is null-terminated. |
| STATUS_BUFFER_OVERFLOW | This warning status means that the concatenation operation did not complete because of insufficient buffer space. The destination buffer contains a truncated, null-terminated version of the intended result. |
| STATUS_INVALID_PARAMETER | This error status means that the function received an invalid input parameter. For more information, see the following list. |
RtlUnicodeStringCat returns the STATUS_INVALID_PARAMETER value when one of the following occurs:
- The contents of a UNICODE_STRING structure are invalid.
- The destination buffer is already full.
- A buffer pointer is NULL.
- The destination buffer's length is zero, but a nonzero length source string is present.
For information about how to test NTSTATUS values, see Using NTSTATUS Values.
Comments
The RtlUnicodeStringCat function uses the destination buffer's size to ensure that the concatenation operation does not write past the end of the buffer. The function does not terminate the resultant string with a NULL character.
If the source and destination strings overlap, the behavior of the function is undefined.
The SourceString and DestinationString pointers cannot be NULL. If you need to handle NULL pointer values, use RtlUnicodeStringCatEx.
For more information about the safe string functions, see Using Safe String Functions.
Requirements
IRQL: PASSIVE_LEVEL
Headers: Declared in Ntstrsafe.h. Include Ntstrsafe.h. Link to Ntstrsafe.lib.
See Also
RtlUnicodeStringCatEx, UNICODE_STRING