Windows Driver Kit: Kernel-Mode Driver Architecture
RtlUnicodeStringCopy
The RtlUnicodeStringCopy function copies a string from one UNICODE_STRING structure to another.
NTSTATUS
RtlUnicodeStringCopy(
OUT PUNICODE_STRING DestinationString,
IN PCUNICODE_STRING SourceString
);
Parameters
- DestinationString
- A pointer to a UNICODE_STRING structure. The source string is copied to 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 copied to the destination string. The maximum number of bytes in the structure's string buffer is NTSTRSAFE_UNICODE_STRING_MAX_CCH * sizeof(WCHAR).
Return Value
RtlUnicodeStringCopy returns one of the following NTSTATUS values.
| Return value | Meaning |
|---|
| STATUS_SUCCESS | This success status means that source data was present, the string was copied without truncation, and the resultant destination buffer is null-terminated. |
| STATUS_BUFFER_OVERFLOW | This warning status means that the copy operation did not complete because of insufficient buffer space. The destination buffer contains a truncated version of the source string. |
| STATUS_INVALID_PARAMETER | This error status means that the function received an invalid input parameter. For more information, see the following list. |
RtlUnicodeStringCopy 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 RtlUnicodeStringCopy function uses the destination buffer's size to ensure that the copy operation does not write past the end of the buffer. If the string must be truncated at the end of the destination 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 the RtlUnicodeStringCopyEx function.
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.
Library: Contained in Ntstrsafe.lib.
See Also
RtlUnicodeStringCopyEx, UNICODE_STRING