Response.BinaryWrite Method

The BinaryWrite method writes the specified information to the current HTTP output without any character conversion. This method is useful for writing nonstring information, such as binary data required by a custom application.



  • data
    The data to write to the HTTP output. This parameter is of type VT_ARRAY | VT_UI1, which is a variant array of unsigned one-byte characters.

Return Values

This method has no return values.

Example Code

If you have an object that generates an array of bytes, you can use the following call to BinaryWrite to send the bytes to a custom application:

Set objBinaryGen = Server.CreateObject("MyComponents.BinaryGenerator")
vntPicture = objBinaryGen.MakePicture
Response.BinaryWrite vntPicture


An ASP application uses internal server buffers when writing data to the client, irrespective of the value of Response.Buffer. As the application is writing data synchronously, the data buffer can be reused when the BinaryWrite function returns, while the server is writing the data asynchronously to the client. The server, in turn, makes a copy of the data into its internal buffers. As a result of this buffering, the ASP application should not try to send unreasonable amounts of data in a single BinaryWrite, but rather break it into fragments so as to avoid running out of buffer space. Should the buffer space be exceeded, ASP error 251, "response exceeds the buffer limit," will be returned. While the default maximum buffer size is 4MB, the server administrator may increase it.

Applies To

Response Object


Client: Requires Windows XP Professional, Windows 2000 Professional, or Windows NT Workstation 4.0.

Server: Requires Windows Server 2003, Windows 2000 Server, or Windows NT Server 4.0.

Product: IIS

See Also