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From: Mark Rodgers (mark.rodgers_at_[hidden])
Date: 2002-07-20 15:52:46

From: "Noel Yap" <yap_noel_at_[hidden]>
> >From what I understand from _C: A Complete Reference_,
> the standard differentiates between the two so that
> #include <stdio.h> will work even on systems where
> stdio.h is an invalid filename. Can anyone confirm
> this?

I don't think that's really true. 16.2/5 says

  "The mapping between the delimited sequence and the
  external source file name is implementation-defined."

It is talking about both h-char-sequences (inside <>)
and q-char-sequences (inside ""), so #include "foo.h"
can also be defined by the implementation to map to a
source file any way it likes, as long as it follows the
rest of 16.2/5. I think that is trying to say that the
implementation must provide a *unique* mapping for a
sequence of nondigits followed by a period and another
single nondigit, but doesn't have to provide a unique
mapping (or perhaps any mapping) for other sequences.

So I think it means #include "foo.h" and #include "bar.h"
must map to different source files, but #include "foo.hpp"
and #include "foo.hxx" are allowed to map to the same file
(maybe they're both foo.h) or might not map to anything.


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