Generic Function

Summary

Returns or changes the current position within a stream.

Package

stream

Signature

stream-file-position stream => position

Signature

(setf stream-file-position) position-spec stream => success-p

Arguments

stream

A stream.

position-spec

A file position designator.

Values

position

A file position or nil.

success-p

A generalized boolean.

Description

The generic function stream-file-position implements file-position.

stream-file-position is called when file-position is called with one argument.

(setf stream:stream-file-position) is called when file-position is called with two arguments.

The return value is returned by file-position. For the setf function, this is a slight anomaly because setf functions normally return the new value. However in this case it should return the success-p value mandated by the ANSI Common Lisp standard.

The default methods specialized on stream return nil.