Check if File Exists

Hi, Eric -

I'd take a different approach to this problem; rather than test for the existence of the file, I'd wrap the "run" call in a "stopped" invocation:

     /ExtraLogo

     {

         /mysaveobj save def                      % Do our bookkeeping

          mark                                              % Push a mark on the stack

          {  (6661.EPS) run } stopped          % Try to execute the file

          { (File failed) = } if                         % If it fails, emit a simple error message

          cleartomark                                   % Clean up the stack

          mysaveobj  restore                         % Reclaim VM

     } def

Note that the code in the "if" procedure body can be anything you wish, including an alternative version of the logo.

In the interest of robustness, you should arguably always execute an external file in a stopped context. I presume you are also doing all the other good practices, such as doing a save and restore around the external call.

The nice thing about this approach is that it will catch anything that goes wrong with the execution of the file: permission problems, errors in the PS code, etc.

If you're interested, there's an article on using EPS files in handwritten PS code in the November 2004 issue (#36) of the Acumen Journal (www.acumentraining.com/acumenjournal.html).

- John

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John Deubert

Acumen Training

PostScript & PDF consulting and training

www.acumentraining.com

How about taking Helge's suggestion and writing something like this:

(queried.eps) dup status true {run  %runs queried.eps file if it exists

}

{pop  %pops the string (queried.eps) off the operand stack and then goes on to the next part of your PS program

}ifelse

Look into the PLRM for the status operator. If the file exists, it returns - among a couple of properties - true and false

otherwise (see the PLRM for details)

Helge