IByteBuffer::SetSize method

Article
01/07/2021

[The SetSize method is available for use in the operating systems specified in the Requirements section. It is not available for use in Windows Server 2003 with Service Pack 1 (SP1) and later, Windows Vista, Windows Server 2008, and subsequent versions of the operating system. The IStream interface provides similar functionality.]

The SetSize method changes the size of the stream object.

Syntax

HRESULT SetSize(
  [in] LONG libNewSize
);

Parameters

libNewSize [in]: New size of the stream as a number of bytes

Return value

The return value is an HRESULT. A value of S_OK indicates the call was successful.

Remarks

The IByteBuffer::SetSize method changes the size of the stream object. Call this method to preallocate space for the stream. If the libNewSize parameter is larger than the current stream size, the stream is extended to the indicated size by filling the intervening space with bytes of undefined value. This operation is similar to the IByteBuffer::Write method if the seek pointer is past the current end-of-stream.

If the libNewSize parameter is smaller than the current stream, then the stream is truncated to the indicated size.

The seek pointer is not affected by the change in stream size.

Calling IByteBuffer::SetSize can be an effective way of trying to obtain a large chunk of contiguous space.

Examples

The following example shows setting the buffer size.

LONG     lNewSize = 256;
HRESULT  hr;

// Change the buffer size.
hr = pIByteBuff->SetSize(lNewSize);
if (FAILED(hr))
  printf("Failed IByteBuffer::SetSize\n");

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
End of client support	Windows XP
End of server support	Windows Server 2003
Header	Scardssp.h
Type library	Scardssp.tlb
DLL	Scardssp.dll
IID	IID_IByteBuffer is defined as E126F8FE-A7AF-11D0-B88A-00C04FD424B9

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