[bug-gs] GS bug 207738 "restore" sometimes fails with "invalidrestore"

[Ray Johnston]

Richard,

The problem with interactive processing (from the GS> prompt) is that
the 'executive' works from a %statementedit stream that is executed.
The stream that contains the 'save' is discarded after it is executed.
The stream that contains the 'restore' is allocated after the 'save',
but still in existence at the time the 'restore' is attempted, so this
causes the invalidrestore condition.

To change this would require that the stream be allocated outside the
VM spaces affected by save/restore -- not an easy thing to do and
keep integrity of the allocators.

L. Peter Deutsch dug into this and determined that Adobe PS
interpreters behave similarly, although I haven't attempted to
verify that independently with port 9100 to a network connected
Adobe PS printer (which invokes 'executive').

Regards,
Ray Johnston
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Richard A. Reitmeyer wrote:

> Hello.
> 
> I've got the same problem as described in GS bug 207738: I don't
> understand why I'm getting "invalidrestore," and my efforts to
> narrow the scope of my problem eventually lead me to 
> GS> save
> GS<1> restore
> Error: /invalidrestore in --restore---
> 
> Having read Ghostscript bug 207738, my problem is apparently me.
> 
> Could you enlighten me?
> 
> Richard
-- 
Ray Johnston
Director of Engineering                          Tel: (714) 484-0376
Artifex Software Inc.                            Fax: (714) 220-1022
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