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From: glenn@heaven.woodside.ca.us (Glenn Reid)
Newsgroups: comp.sys.next
Subject: Re: DPS dictfull error with Win3 PS files
Keywords: where known
Message-ID: <471@heaven.woodside.ca.us>
Date: 7 Apr 91 20:56:25 GMT
References: <1542@cgh.UUCP>
Sender: glenn@heaven.woodside.ca.us
Lines: 28

Paul Homchick writes

> In using the postscript driver for the NEC, windows was including the
> following PS sequence:
> 
> 	{statusdict begin 2 setpapertray end }stopped pop
> 
> My correspondent mentioned that "There are better ways to safely
> execute a PS operator if it [might] not be present".  Now, I'm
> curious, does anyone know the correct way of doing this?

There are two operators that are designed for this kind of thing.
They are "where" and "known".  Since "statusdict" may be missing in
addition to "setpapertray", you should check for both of them.

Here is a reasonable way to execute this kind of code:

/statusdict where { %if
    pop
    statusdict begin
        /setpapertray where { pop 2 setpapertray } if
    end
} if

--
 Glenn Reid				RightBrain Software
 glenn@heaven.woodside.ca.us		NeXT/PostScript developers
 ..{adobe,next}!heaven!glenn		415-851-1785 (fax 851-1470)