Re: [boost] Coding guidelines - #include

From: Bill Seymour (bsey_at_[hidden])
Date: 2001-07-06 08:02:43

>
> It looks like all this stuff like 'q-char-seq' goes back to
> C89/90, ...
>

Yes.

>
> All I can conclude from the standard is that
>  - there are two ways of including things
>  - both have implementation-defined behavior
>  - they're potentially different, but may work the same
>  - #include<...> must work with standard headers
>

Yes.

>
> 'header' vs. 'source file': are they disjoint, or is
> one a subset of the other?
>

Unfortunately, neither is a subset of the other.  Obviously,
there can be a source file that's not a header; and there
can also be a header, or at least a standard header, that's
not a source file.  Implementations are free to see something
like "#include <stddef.h>" and just set a switch in the compiler
that makes all the appropriate names visible.  This is quite
deliberate and was done mainly for the sake of free-standing
implementations that might lack even the concept of a "file;"
but it can also be used as a compile-time optimization by
hosted implementations.

--Bill Seymour