RtlCopyUnicodeString function (wdm.h)

Article
02/22/2024

The RtlCopyUnicodeString routine copies a source string to a destination string.

Syntax

NTSYSAPI VOID RtlCopyUnicodeString(
  [in, out]      PUNICODE_STRING  DestinationString,
  [in, optional] PCUNICODE_STRING SourceString
);

Parameters

[in, out] DestinationString

A pointer to the destination string buffer. This parameter points to a UNICODE_STRING structure.

[in, optional] SourceString

A pointer to the source string buffer. This parameter points to a UNICODE_STRING structure.

Return value

None

Remarks

If SourceString is NULL, this routine sets the Length field of the structure pointed to by DestinationString to zero.

This routine does not modify the MaximumLength and Buffer fields of the structure pointed to by DestinationString.

The number of bytes copied from the source string is either the source string length (specified by the Length member of the structure pointed to by SourceString) or the maximum length of the destination string (specified by the MaximumLength member of the structure pointed to by DestinationString), whichever is smaller.

The caller must properly initialize all members of the structure pointed to by DestinationString before calling RtlCopyUnicodeString. Failure to initialize the Length or the MaximumLength member before calling this routine can cause a buffer overrun.

The DestinationString and SourceString buffers must be resident if the caller is running at IRQL >= DISPATCH_LEVEL.

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows 2000.
Target Platform	Universal
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h, Wudfwdm.h)
Library	NtosKrnl.lib
DLL	NtosKrnl.exe (kernel mode); Ntdll.dll (user mode)
IRQL	Any level (See Remarks section)