Re: ISO/IEC 14519 - Ada POSIX binding

[tmoran@acm.org]

>Even with Ada 83, they should have used an errno-like variable and a
>single exception.  (In Ada 95, you can encode the error code in the
>exception message.)  The long exception list results in lots of "when
>others =>" clauses silently discarding the exception if you want to
>have reliable code which runs on real-world systems.
  You are laboring under a misunderstanding.  The Posix binding does not
have a "long exception list" and does not add new exceptions willy-nilly.
As pointed out by Dave Emery, new error codes get added and it would be
absurd to add new exceptions to the "standard" and ask people to add new
exception handlers to their programs.  There is an exception
Posix.Posix_Error to force the program not to ignore problems.  The
program must then get the particular error code and figure out what to do.
I suppose that might translate into "when others =>" in a case statement
in old code, but it would be a bad programmer indeed who decided "There's
an error.  I don't understand it.  I'll just pretend I didn't notice it".