Path: utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!ncis!helios.ee.lbl.gov!pasteur!ucbvax!decwrl!purdue!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Preprocessor question
Message-ID: <9433@smoke.BRL.MIL>
Date: 19 Jan 89 13:26:42 GMT
References: <531@ole.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 14

In article <531@ole.UUCP> ray@ole.UUCP (Ray Berry) writes:
>#define VAL 3
>#define STR(x) #x
>  puts("val is " STR(VAL));
>   Turbo C produces "3" for STR(VAL); Microsoft produces "VAL" and 
>leaves it at that.  
>   Which behavior is correct?

"Before being substituted, each argument's preprocessing tokens are
completely macro replaced as if they formed the rest of the
translation unit; no other preprocessing tokens are available."

So VAL is first expanded to 3 then the #3 is performed to produce
"3".