friendly messages

[Peter da Silva]

In article <9780 at smoke.BRL.MIL>, gwyn at smoke.BRL.MIL (Doug Gwyn ) writes:
> In article <3283 at ficc.uu.net> peter at ficc.uu.net (Peter da Silva) writes:
> >Have you looked at the new "perror()" docs? They describe a 4-component
> >error message format for all programs to use...

> perror() CANNOT do this, as its interface is standardized and has no
> room for the additional information (severity and object; the program
> name can and probably should be automated).

I realise this. The document describes what programs should do for error
messages, but makes no recommendation as to how this should be done.

> Presumably there is an
> analogous function that accepts the additional information.

Unfortunately it's like Open Look... they just specced what it should look
like without providing a programmer interface. The documentation has been
out in the bookstores for some time: it's a red book with a plastic spiral
binding.

> What is supposed to be done when there is no particular object?
> 	prog: fatal: ???: Insufficient memory available

What does perror do when there is no particular object?

	if(!(buffer = malloc(BUFSIZ*NUMBUFS))) {
		perror(.....?.....);
		...
	}

Same problem.

Perhaps we (the usenet community) should spec a better interface:

extern char *progname;
extern char *errformat;
extern char default_errformat[];
char *errmsg();

main(argc, argv)
int argc;
char **argv;
{
	progname = argv[0];
	errformat = getenv("ERRORFORMAT");
	if(errformat == NULL)
		errformat = default_errformat;
...
}

...
	fprintf(stderr, "%s\n", errmsg(object, severity));

errformat would be printf/sccs-like:

	%p	program name
	%P	program name, tail only (no path).
	%o	object
	%e	error message
	%E	short error message
	%s	severity
	%S	severity, 1 char
	%E	%p: %s: %o: %e
	%Q	%o: %e
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Work: uunet.uu.net!ficc!peter, peter at ficc.uu.net, +1 713 274 5180.   `-_-'
Home: ...!texbell!sugar!peter, peter at sugar.hackercorp.com.            'U`
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