On 2008 May 11, at 5:09, PR Stanley wrote:
Um, I was encountering and recognizing times when I
really needed an
out-of-band "null", and the pain of representing such in C,
shortly
after I started serious programming in C (call it 1984-5). Is
this
really difficult?
Paul: Hmm, I'm not quite sure what you're driving at.
Me neither.
Null pointers, EOF markers, didn't find specified key in some tree,
etc.
Paul: So much time is wasted on making the thing work even if
you have perfectly sound semantics. Still, that's a hundred times
more preferable to c++ and its anomalies and contradictions. What
was Stroustroup thinking of! :-
My real point was that in the C programming culture it was/is far too
common to use an in-band value; that is, one that could be confused
with or treated as a valid response: null pointers, stdio's EOF (=
-1). This just causes problems because code is almost encouraged to
ignore the special cases. For example, the ctype macros have to
support being passed EOF. Maybe types force you to deal with it,
while simultaneously providing convenience functions to help you deal
with it.
--
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED]
system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED]
electrical and computer engineering, carnegie mellon university KF8NH
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