[Zope] Error codes

[Graham King]

This may have been done to death before.... bear with me.

Have searched around a fair bit for the meaning of "error codes", as in the
ubiquitous 
"Aiieee! 10318 exited with error code: 138"

Can anybody direct me to a repository where these specific errors are
documented, what they mean, and how many there might be?

(My memories of shelves full of books of documentation, and the biblical
"System Error Messages and Codes", are receding even as mainframes wisp away
into the mists of Avalonic myth).


cheers
Graham