Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!cornell!uw-beaver!teknowledge-vaxc!sri-unix!quintus!jbeard
From: jbeard@quintus.uucp (Jeff Beard)
Newsgroups: comp.lang.c
Subject: Re: `static'
Message-ID: <255@quintus.UUCP>
Date: 5 Aug 88 23:09:12 GMT
References: <644@m10ux.UUCP> <503@draken.nada.kth.se> <12840@mimsy.UUCP>
Sender: news@quintus.UUCP
Reply-To: jbeard@quintus.UUCP (Jeff Beard)
Organization: Quintus Computer Systems, Inc: Mountain View, Ca
Lines: 32


% Finally, returning to string constants: these are unnamed objects, and
% hence the scoping rules for names are irrelevant.  There simply is no
% name to be scoped.  The objects do, however, have static storage duration:
% they exist at all times.  Thus, once you have a pointer to a string
% constant, you can follow that pointer at any time.  The string shall
% not vanish from underfoot, unless the whole program vanishes with it.

1) program scoped static char * foo may be altered anywhere by any procedure
   and thus the original string reference will be lost to all, even though 
   the string it self persists.

	static char * header;

	header = "  Center Heading For Report  ";

	....
	printf(header);	/* performs as expected */
	....

	header = "  Center Footing For Report  ";
	....

	printf(header);	/* yields a FOOTING as a Header ... OhMy! */

2) which brings up another storage class often forgotten altogeter:

	READONLY as in a format string given for printf()

	printf("text %c not of type %s\n" args, ..);

	xstr() collects said strings to reduce storage costs at possible
	expense of memory thrashing to get at a non-local page.