[boost] Re: #pragma once

From: Gennaro Prota (gennaro_prota_at_[hidden])
Date: 2002-12-30 10:06:48

On Mon, 30 Dec 2002 00:07:19 -0800, "Paul Mensonides"
<pmenso57_at_[hidden]> wrote:

>Do you mean that the actual headers must be structured in such a way as to
>only get included once?  In other words, to have a inclusion tree that is
>invariant?  Or do you mean that the compiler should only process a file one
>time by default?  The first will end up causing more processing to be done
>as more code than necessary gets included, and the second will break the
>pp-lib altogether (it relies on multiple inclusion of the same file).

The latter. But I wasn't suggesting to change the language _now_. I
was just saying that, if we started from scratch, we would probably
adopt that rule and introduce a special directive, say

   #allow_reinclude

for the rare cases (assert.h, and a few others) where multiple
inclusion is desired.

Genny.