From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
Date: Tue,  1 Aug 2000 08:53:27 +0000
From: "Douglas A. Gwyn" <gwyn@arl.army.mil>
Message-ID: <3985E318.10B7E8F8@arl.army.mil>
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References: <200007311515.LAA18248@cse.psu.edu>
Subject: Re: [9fans] Installing the updates
Topicbox-Message-UUID: f04295ca-eac8-11e9-9e20-41e7f4b1d025

rob pike wrote:
> Seriously, we deliberately refused to buy into that multiple
> inclusion dance, which is a hideous non-solution for the problem
> of undefined dependency order on #includes.  Why not use the
> occasion to clean up the code so you only include <stdio.h> once?

One doesn't always have that option; for example, a header file
might be part of somebody else's project on a machine far, far away.
/* imported.h */
#include <stdio.h> /* need FILE decl */
extern imp_read( FILE*, char *whatever );

Many developers take the approach that each interface header
should be self-contained, so that the user of the header doesn't
need to know anything about the details of the implementation of
that header.  Information hiding, you know.

Since the C standard definitely requires idempotency for the
standard headers (except <assert.h>), at least the APE headers
ought to conform, to ease the burden of importing non-native code.