Re: Why would anyone want opacity?

[Guillermo J. Rozas <gjr@martigny.ai.mit.edu>]

|   Date: Thu, 09 May 1996 14:56:50 -0400
|   From: Matthias Blume <blume@CS.Princeton.EDU>
|
|   Like, for example, this: ``Implementations are permitted, but not
|   required to implement a procedure KRPFHGH.  Arguments, result,
|   effects, and purpose of KRPFHGH, however, are left unspecified by this
|   report.''
|
|   In other words: what good would such an addendum do?

Come on, you must be joking at this point.

The issue is more like

"If the facility is present, it should conform to the following
interface."

An implementation-specific manual would then describe the variation or
constraints from the addendum in the report.

I guess you don't believe in the Unix call readdir or the
corresponding NT call to read a directory just because the semantics
are not very precise.  However, I'd hate to use a file system that did
not provide for the ability to list the contents of directories, or
have use a different procedure in each version/variant of Unix.