VMS extensions

[Patrick Nolan]

Help!  I am baffled by some non-standard syntax which I think is
a VMS C extension.  I have source code for a very VMS-specific
program.  We are too cheap to buy DEC's compiler, so I am trying
to make it work with gcc (1.22).  I have run up against some
non-standard constructs: variant_union and variant_struct.
I tried changing these to union and struct, with disastrous results.
Can someone who understands VMS C explain what these things are?
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 Patrick Nolan                    Bitnet: PLN at SLACVM 
 W. W. Hansen Laboratories        Internet: nolan at meggie.stanford.edu
 Stanford University                        nolan at portia.stanford.edu