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RtlInitUnicodeString routine

The RtlInitUnicodeString routine is obsolete and is exported only to support existing driver binaries. Drivers should use the safe-string routines RtlUnicodeStringInit and RtlUnicodeStringInitEx instead.

Syntax


VOID RtlInitUnicodeString(
  _Out_     PUNICODE_STRING DestinationString,
  _In_opt_  PCWSTR SourceString
);

Parameters

DestinationString [out]

A pointer to the UNICODE_STRING structure to be initialized.

SourceString [in, optional]

A pointer to a null-terminated wide-character string. This string is used to initialize the counted string pointed to by DestinationString.

Return value

None

Remarks

This routine initializes a counted string of Unicode characters.

The routine copies the SourceString pointer value to the Buffer member of the UNICODE_STRING structure pointed to by DestinationString. The Length member of this structure is set to the length, in bytes, of the source string, excluding the terminating null. The MaximumLength member of the structure is set to the length, in bytes, of the source string, including the terminating null. If SourceString is NULL, Length and MaximumLength are both set to zero.

RtlInitUnicodeString does not alter the source string pointed to by SourceString.

Note  If the source string is longer than MAX_USTRING - 1 bytes, RtlInitUnicodeString sets the Length member of the UNICODE_STRING structure pointed to by DestinationString to MAX_USTRING - 2, and sets the MaximumLength member of this structure to MAX_USTRING. In this case, the Length and MaximumLength values misrepresent the length of the null-terminated source string, and relying on the accuracy of these values is potentially dangerous.

Callers of RtlInitUnicodeString can be running at IRQL <= DISPATCH_LEVEL if the DestinationString buffer is nonpageable. Usually, callers run at IRQL = PASSIVE_LEVEL because most other RtlXxxString routines cannot be called at IRQL > PASSIVE_LEVEL.

Requirements

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

See Remarks section.

See also

RtlUnicodeStringInit
RtlUnicodeStringInitEx
UNICODE_STRING

 

 

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