xfuncs, bb_ funcs and "nofork/noexec" plans

[Denis Vlasenko]

On Friday 10 March 2006 22:01, Rob Landley wrote:
> > We can even have both:
> 
> If X can replace Y then you don't need both.  If you need both, it's because X 
> can't really replace Y, which is a defect in X.
> 
> > 	xlookup_host(&s_in, argv[optind]); //Will die with default error msg
> >
> > 	lookup_host_or_die(&s_in, argv[optind], "\0x3" "Custom error message and
> > exit code"); --
> 
> Having both is bigger.  The error message string is generally the biggest 
> part.  Moving the test out of line but then supply an extra argument on the 
> stack is not a big win.

Sometimes you want custom error message. patch.c:

        if (fputs(line, dest_stream) == EOF) {
                bb_perror_msg_and_die("Error writing to new file");
        }

We cannot save here on error message.

        xfputs(line, dest_stream);

can give "Write error" at most.
No "Error writing to new file" or "Error writing to '%s'", filename.

        fputs_or_die(line, dest_stream, "new file");

won't save that much, but it will save something AND will provide
meaningful error message.

Why call it fputs_or_die instead of xfputs, then? I think that almost
all currently existing xfuncs have exactly the same parameters as
corresponding C lib funcs:

	void* malloc(size_t sz);
	void* xmalloc(size_t sz /* no extra params! */ );

And I like this. Thus:

        xfputs(line, dest_stream, "new file");	/* breaks that rule */
        fputs_or_die(line, dest_stream, "new file"); /* I think this is better */

--
vda