| Allegro CL version 6.1 Unrevised | |||||||||
Arguments: stream need action
Returns true for success, nil for failure, to extend the underlying device
allocation and/or connection. The need argument is the number
of bytes that will be read or written if the extension is successful,
and the action argument describes the operation being
performed; typical values for action are
:input, :input-check,
:output, and :output-check.
Note that Allegro CL offers calls to device-extend for the following circumstances:
string-output-simple-stream: The action
argument is always :output or
:output-check. If device-extend returns nil, an error is generated. string-input-simple-stream: The action
argument is always :input
or :input-check. The primary method on
this stream simply returns nil, which causes
end-of-file processing to occur. mapped-file-simple-stream:
Read operations pass an :input
or :input-check action. A nil return for a read will cause end-of-file
processing by the read operation. Writes pass an
:output action. If device-extend
returns nil, an error is generated.direct-simple-stream:
returns nil.
string-input-simple-stream: returns nil.
string-output-simple-stream:
:output allocates and copies a new string twice the
current size.
fill-pointer-output-simple-stream:
:output extends the array using adjust-array.
mapped-file-simple-stream: returns nil.
See streams.htm for information on the simple-streams implementation in Allegro CL. The older but still supported Gray streams implementation is described in gray-streams.htm.
Copyright (c) 1998-2001, Franz Inc. Berkeley, CA., USA. All rights reserved.
Documentation for Allegro CL version 6.1 update # 1. This page was not revised.
Created 2001.12.15.
| Allegro CL version 6.1 Unrevised | |||||||||