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Channel - Basic (textual) I/O channel   

Description:
The Channel class implements low-level input/output for the AST library. Writing an Object to a Channel will generate a textual representation of that Object, and reading from a Channel will create a new Object from its textual representation.

Normally, when you use a Channel, you should provide "source" and "sink" functions which connect it to an external data store by reading and writing the resulting text. By default, however, a Channel will read from standard input and write to standard output.

Constructor Function:
astChannel

Inheritance
The Channel class inherits from the Object class.

Attributes
In addition to those attributes common to all Objects, every Channel also has the following attributes:

  • Comment: Include textual comments in output?
  • Full: Set level of output detail
  • Skip: Skip irrelevant data?

Functions
In addition to those functions applicable to all Objects, the following functions may also be applied to all Channels:

  • astRead: Read an Object from a Channel
  • astWrite: Write an Object to a Channel



next up previous
Next: CmpFrame - Compound Frame
Up: AST Class Descriptions
Previous: Axis - Store axis information

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils