Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: `static'
Message-ID: <12891@mimsy.UUCP>
Date: 8 Aug 88 04:06:54 GMT
References: <644@m10ux.UUCP> <503@draken.nada.kth.se> <12840@mimsy.UUCP> <255@quintus.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 45

In article <12840@mimsy.UUCP> [and why does our netnews software use .UUCP?]
I wrote:
>>string constants ... do, however, have static storage duration ....

In article <255@quintus.UUCP> jbeard@quintus.uucp (Jeff Beard) writes:
>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.
[example deleted]

Certainly.

>2) which brings up another storage class often forgotten altogeter:
>	READONLY as in a format string given for printf()

In the dpANS, read-only (called `const') is considered a `qualifier'
rather than a storage class.  Strangely, while "string"s are allowed
to be read-only, they have type `array of char' rather than `array of
const char'.  (I think this is a mistake.)

>	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.

The xstr program actually collects *all* quoted strings, and replaces
each with something of the form `&xstr[<constant>]'.  This is annoying;
the common sequence

	#ifndef lint
	static char sccsid[] = "@(#)blort.c	4.2 (Berkeley) 8/8/88";
	#endif

fails to compile, since it becomes

	static char sccsid[] = &xstr[234];

One must write

	static char *sccsid = "@(#)blort.c	4.2 (Berkeley) 8/8/88";

which wastes a few bytes of storage per sccsid (since each id is
different).
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris