Return type: Switch
Returns:       Returns true if the stream is attached to an object and false otherwise. Replacing is with isnt will reverse the results.

Syntax

stream-name (is | isnt) attached 

A stream test used to determine whether a stream is attached to an object.

Usage Notes

A stream can have three states: unattached (initial state), opened or closed.

Streams may be attached to any one of five objects:

1. Buffers
2. Files
3. Referents
4. External string sink functions
5. #markup-parser

The association between an object and the attached stream can be broken using discard. If the stream was attached to a buffer, discard destroys the buffer.

Related Syntax close discard open reopen set is closed is open set file set referent

Related Concepts Streams: attachments

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