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Defining Output Formats   

As you might expect, you define the formats for output[*] datasets in rather the same way as for input datasets (§[*]), by means of a search list. However, the way this list is used is slightly different in this case.

The output format list is found by translating the environment variable NDF_FORMATS_OUT, which might typically have a definition such as:

setenv NDF_FORMATS_OUT '.,FITS(.fit),FIGARO(.dst),IRAF(.imh)'

Ignoring, for the moment, the `.' at the start, this list defines the names of foreign data formats which are to be recognised when creating new datasets, and associates a file extension with each one. The syntax and restrictions are identical to the NDF_FORMATS_IN list (see §[*]).

There is no requirement for the output formats to be the same as those used for input although, for obvious reasons, they will often be so. You could, however, give your formats different names or file extensions in the output list if you wanted.

The NDF library uses the same commands to perform format conversion for output datasets as for input ones (see §[*]), so the names of output formats should be chosen to select the environment variable containing the appropriate command. Note, however, that the ``NDF_FROM_...'' command will not be used in the case of output datasets.



next up previous
Next: Specifying an Output Format
Up: SETTING UP FOR FORMAT CONVERSION
Previous: Writing Format Conversion Utilities


Starlink System Note 20
R.F.Warren-Smith & D.S.Berry
17th July 2000
E-mail:ussc@star.rl.ac.uk

Copyright © 2000 Council for the Central Laboratory of the Research Councils