How do I find the length of a field that is externally defined?

How do I find the length  of a data structure that is externally defined?

When I write a subfile record I generally include a hidden field which
contains an image of the record from the disk file.  This proves useful for
refreshing the screen, checking for changes at another work station, and
prevents the need for another chain to the record if the user chooses to 
work with the data.

I usually externally define a data structure like the data record.  On the
display file I define a hidden field to hold the datastructure, but I never
really know the length of the data structure.

Is there anyway to create a REF or REFFLD for an external data structure or
a record format?
 
 
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Booth Martin http://www.MartinVT.com
Booth@xxxxxxxxxxxx
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