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AST_READ
-
Read an Object from a Channel
- Description:
- This function reads the next Object from a Channel and returns a
pointer to the new Object.
- Invocation:
- RESULT = AST_READ( THIS, STATUS )
- Arguments:
-
THIS = INTEGER (Given)
-
Pointer to the Channel.
-
STATUS = INTEGER (Given and Returned)
-
The global status.
- Class Applicability:
-
FitsChan
-
All successful use of AST_READ on a FitsChan is destructive, so that
FITS header cards are consumed in the process of reading an Object,
and are removed from the FitsChan (this deletion can be prevented
for specific cards by calling the FitsChan
AST_RETAINFITS routine).
An unsuccessful call of
AST_READ
(for instance, caused by the FitsChan not containing the necessary
FITS headers cards needed to create an Object) results in the
contents of the FitsChan being left unchanged.
-
StcsChan
-
The AST Object returned by a successful use of
AST_READ
on an StcsChan, will be either a Region or a KeyMap, depending
on the values of the StcsArea, StcsCoords and StcsProps
attributes. See the documentation for these attributes for further
information.
- Returned Value:
-
AST_READ = INTEGER
-
A pointer to the new Object. The class to which this will
belong is determined by the input data, so is not known in
advance.
- Notes:
- A null Object pointer (AST__NULL) will be returned, without
error, if the Channel contains no further Objects to be read.
- A null Object pointer will also be returned if this function
is invoked with STATUS set to an error value, or if it should fail
for any reason.
Next: AST_REBINX - Rebin a region of a data grid
Up: AST Routine Descriptions
Previous: AST_RATEMAP - Create a RateMap
AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk
Copyright (C) 2009 Science \& Technology Facilities Council