def-stream-class

Arguments: class-name superclasses slots &rest options

This macro is similar to defclass, except that various stream accounting is performed. If a slot is mentioned that is already known to the Allegro CL streams system, it is given a fixed-index value. Also, if an :initform or :logior option is specified, then an initialize-instance :before method is automatically created to ensure that the slot has the specified value before shared-initialize time.

The :logior option is an Allegro CL-specific variant of an initform. Specifying :logior 128 means apply logior to 128 and the previous value of the slot (which should be numeric and defaults to 0). This is a shorthand for specifying a value for the slot in a much more complicated way, and it requires the :before referenced above because it is not a standard CLOS feature.

You must load the :iodefs module to use this macro. Do that by evaluating (require :iodefs). (It is not an error to evaluate that form if the module is already loaded.) This macro is intended for implementing device-level functionality and should not be used except for that purpose. See Simple-stream Description in streams.htm for a description of the device-level.

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

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This page was not revised from the 8.1 page.
Created 2010.1.21.