RtlStringCbCopyUnicodeStringEx function

The RtlStringCbCopyUnicodeStringEx function copies the contents of a UNICODE_STRING structure to a specified destination.

Syntax


NTSTATUS RtlStringCbCopyUnicodeStringEx(
  _Out_     NTSTRSAFE_PWSTR  pszDest,
  _In_      size_t           cbDest,
  _In_      PCUNICODE_STRING SourceString,
  _Out_     NTSTRSAFE_PWSTR  *ppszDestEnd,
  _Out_opt_ size_t           *pcbRemaining,
  _In_      DWORD            dwFlags
);

Parameters

pszDest [out]

Optional. A pointer to a buffer that receives the copied string. The string that the SourceString parameter's UNICODE_STRING structure points to is copied to the buffer at pszDest and terminated with a null character. This pointer can be NULL, but only if STRSAFE_IGNORE_NULLS is set in dwFlags.

cbDest [in]

The size, in bytes, of the destination buffer. The buffer must be large enough for the string and the terminating null character. The maximum number of bytes in the buffer is NTSTRSAFE_MAX_CCH * sizeof(WCHAR).

SourceString [in]

Optional. A pointer to a UNICODE_STRING structure that contains the string to be copied. The maximum number of bytes in the string is NTSTRSAFE_UNICODE_STRING_MAX_CCH * sizeof(WCHAR). This pointer can be NULL, but only if STRSAFE_IGNORE_NULLS is set in dwFlags.

ppszDestEnd [out]

Optional. If the caller supplies a non-NULL address pointer, then after the copy operation completes, the function loads that address with a pointer to the destination buffer's resulting NULL string terminator.

pcbRemaining [out, optional]

Optional. If the caller supplies a non-NULL address pointer, the function loads the address with the number of unused bytes that are in the buffer that pszDest points to, including bytes that are used for the terminating null character.

dwFlags [in]

One or more flags and, optionally, a fill byte. The flags are defined as follows:

STRSAFE_FILL_BEHIND_NULL

If this flag is set and the function succeeds, the low byte of dwFlags is used to fill the portion of the destination buffer that follows the terminating null character.

STRSAFE_IGNORE_NULLS

If this flag is set, either the source or destination pointer, or both, can be NULL. RtlStringCbCopyUnicodeStringEx treats NULL source buffer pointers like empty strings (TEXT("")), which can be copied. NULL destination buffer pointers cannot receive nonempty strings.

STRSAFE_FILL_ON_FAILURE

If this flag is set and the function fails, the low byte of dwFlags is used to fill the entire destination buffer, and the buffer is null-terminated. This operation overwrites any preexisting buffer contents.

STRSAFE_NULL_ON_FAILURE

If this flag is set and the function fails, the destination buffer is set to an empty string (TEXT("")). This operation overwrites any preexisting buffer contents.

STRSAFE_NO_TRUNCATION

If this flag is set and the function returns STATUS_BUFFER_OVERFLOW, the contents of the destination buffer are not modified.

Return value

RtlStringCbCopyUnicodeStringEx returns one of the following NTSTATUS values.

Return codeDescription
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 space in the destination buffer. If STRSAFE_NO_TRUNCATION is set in dwFlags, the destination buffer is not modified. If the flag is not set, the destination buffer contains a truncated version of the copied string.

STATUS_INVALID_PARAMETER

This error status means that the function received an invalid input parameter. For more information, see the following list.

 

RtlStringCbCopyUnicodeStringEx returns the STATUS_INVALID_PARAMETER value when one of the following occurs:

  • The contents of the UNICODE_STRING structure are invalid.
  • An invalid flag is specified in dwFlags.
  • The value in cbDest is larger than the maximum buffer size.
  • The destination buffer (which pszDest points to) is already full.
  • A buffer pointer is NULL and the STRSAFE_IGNORE_NULLS flag is not specified.
  • The destination buffer pointer is NULL, but the buffer size is not zero.
  • The destination buffer pointer is NULL or its length is zero, but a nonzero length source string is present.

For information about how to test NTSTATUS values, see Using NTSTATUS Values.

Remarks

The RtlStringCbCopyUnicodeStringEx function uses the destination buffer's size (which the cbDest parameter specifies) to ensure that the copy operation does not write past the end of the buffer.

RtlStringCbCopyUnicodeStringEx adds to the functionality of the RtlStringCbCopyUnicodeString function by returning a pointer to the end of the destination string and the number of bytes that are left unused in that string. You can pass flags to the function for additional control.

If the source and destination strings overlap, the behavior of the function is undefined.

The SourceString and pszDest pointers cannot be NULL unless the STRSAFE_IGNORE_NULLS flag is set in dwFlags. If STRSAFE_IGNORE_NULLS is set, one or both of these pointers can be NULL. If the pszDest pointer is NULL, the SourceString pointer must be NULL or the UNICODE_STRING structure must describe an empty string.

For more information about the safe string functions, see Using Safe String Functions.

Requirements

Target platform

Desktop

Version

Available in Windows XP with Service Pack 1 (SP1) and later versions of Windows.

Header

Ntstrsafe.h (include Ntstrsafe.h)

Library

Ntstrsafe.lib

IRQL

PASSIVE_LEVEL

See also

RtlStringCbCopyUnicodeString
RtlStringCchCopyUnicodeStringEx
UNICODE_STRING

 

 

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