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Allegro CL version 8.2
Unrevised from 8.1 to 8.2.
8.1 version


Arguments: (var buffer &key external-format) forms

Broadly similar to with-output-to-string but with an octet buffer (a vector that is a simple-array with element type (unsigned-byte 8) or (signed-byte 8)) instead of a Lisp string. (Unlike with-output-to-string, which accepts adjustable strings and strings with fill pointers, with-output-to-buffer will not accept a vector with fill pointer nor an adjustable vector.)

The external-format argument should be the name of an external-format, or :default. :default will cause the external format to be looked up in the locale. with-output-to-buffer is implemented using a buffer-output-simple-stream.

The buffer argument can either be an octet buffer (described above) or nil. If it is nil, the stream acts like a counting bit-bucket: no output is generated, and so no overflow can occur, but the file-position of the stream can be queried at the end of the write. This allows the following to be done:

cl-user(1): (with-output-to-buffer (stm nil)
              (write-string "hello" stm)
              (file-position stm))

The macro with-underlying-simple-vector may be useful in conjunction with this macro as it allows any (unsigned-byte 8) or (signed-byte 8) array (not just simple one or just vectors) to be effectively used as the buffer.

See streams.htm for information on the simple-streams implementation in Allegro CL.

Copyright (c) 1998-2015, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 8.2. This page was not revised from the 8.1 page.
Created 2010.1.21.

Allegro CL version 8.2
Unrevised from 8.1 to 8.2.
8.1 version