The CUPS log files only contain messages appropriate to the user-selected log level. CUPS does the selection via prefixes in the messages which backends and filters send to STDERR. Error messages of ESP GhostScript were appropriately prefixed. With this report I suggest this prefixing for GPL GhostScript, as it will replace ESP GhostScript in the distros when the merger has completed. See the attached patch to apply the prefixing.
Created attachment 2925 [details] Makes error and warning messages get prefixed for correctly appearing in CUPS logs
CUPS is not the only consumer of Ghostscript messages. Font downloaders, spoolers, and PostScript drivers that use bi-directional communication relay on the traditional form of the error message: %%[ Error: ... ]%% We need an option to select the format.
There are two possible solutions: One is allowing to choose between the standard GhostScript and the CUPS message format by a command line option or let the pstoraster filter (contrib/cups/pstoraster.in in the merged GhostScript from http://www.linuxprinting.org/download/printing/esp-gpl-ghostscript-merge/README) filter and convert the messages. The second has the advantage of not having any impact on core GhostScript and not needing to be commercially distributable in GhostScript. The conversion can probably easily be done with some Perl or sed magic.
The errorhandler that displays %%[Error... messages can be changed when gs is used with CUPS.
This is part of the CUPS migration, so assigning to Till.
Enhancement still missing in Ghostscript 9.03
After 12 years we think this one can be resolved as 'WONTFIX'