Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!ucsfcgl!cca.ucsf.edu!rk9005
From: rk9005@cca.ucsf.edu (Roland McGrath)
Newsgroups: comp.lang.c
Subject: Functions that return pointers to unmodifiable data
Message-ID: <1140@ucsfcca.ucsf.edu>
Date: 22 Jan 88 06:47:46 GMT
Reply-To: roland@rtsg.lbl.gov (Roland McGrath)
Organization: Hackers Anonymous International, Ltd., Inc. (Applications welcome)
Lines: 16

Is there some reason why the ANSI C standard does not declare strerror:
	const char *strerror(int errnum);
?

It seems to me that it should be made clear that the user program
may not modify the data that the return value of strerror points to.
Also, if sys_errlist (or whatever) is defined:
	const char *sys_errlist[] = { "Error 0", /* ... */ };
Whether or not it is defined "const", in some implementations
(such as GCC), the string literals are put in read-only memory,
so attempting to write in the space pointed to by the return
of strerror may cause a trap.
-- 
		Roland McGrath
UUCP: 			...!ucbvax!lbl-rtsg.arpa!roland
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