Path: utzoo!attcan!uunet!mcvax!philmds!leo
From: leo@philmds.UUCP (Leo de Wit)
Newsgroups: comp.lang.c
Subject: Re: Modifying string literals (was Re: Are strings local?)
Keywords: Help!
Message-ID: <574@philmds.UUCP>
Date: 5 Aug 88 22:03:44 GMT
References: <644@m10ux.UUCP> <12791@mimsy.UUCP> <652@m10ux.UUCP> <24986@think.UUCP>
Reply-To: leo@philmds.UUCP (Leo de Wit)
Organization: Philips I&E DTS Eindhoven
Lines: 22

In article <24986@think.UUCP> barmar@kulla.think.com.UUCP (Barry Margolin) writes:
>In article <652@m10ux.UUCP> rgr@m10ux.UUCP (Duke Robillard) writes:
>>During my search about this locality of statics business, I discovered
>>a pretty bizarre thing about strings.  I dunno if it's just my System
>>V compiler or what, but you can write to strings (since they're just
>>static arrays of characters?)
>
>Yes, compilers will allow this, but it is not a good idea, and I
>believe that ANSI C specifically says that it is a no-no.  A compiler
>is permitted to allocate string literals in read-only memory.  I think
   [rest deleted]...

Indeed. The VMS C compiler does just this.
I believe something like

   tmpnam("fooXXXXXX");

where tmpnam should fill in the XXXXXX with a (process unique?) id,
just stack dumped because it tried to write into readonly memory.
Not that I'm suggesting anyone should use VMS or VMS C ........ 8-).

     Leo.