Date: Tue, 31 Jul 2001 11:50:11 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Will R <forkazoo2 AT aol DOT com>
cc: djgpp AT delorie DOT com
Subject: Re: Making OS-independent code little easier...
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On 31 Jul 2001, Will R wrote:

> >#ifndef    __OS__H
> >#define    __OS_H
> >
> >#ifndef    __LINUX__
> >    #ifdef    LINUX
> >        #define    __LINUX__   
> 
> just one thing -- aren't double underscores not allowed in user
> land?

You are not allowed to _define_ macros which begin with two
underscores, but you are certainly allowed to _depend_ on them.

(Actually, ``are not allowed'' is not accurate here: the ANSI/ISO
standard says that those names are ``reserved for the
implementation''.  Which simply means that it's unsafe to define any
such names in application-level code: you might break the compiler,
the library, or your code.)