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.