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Message-ID: <Ze4zaiYQYOI4xHxf@debian>
Date: Sun, 10 Mar 2024 23:25:40 +0100
From: Alejandro Colomar <alx@...nel.org>
To: Rich Felker <dalias@...c.org>
Cc: NRK <nrk@...root.org>, Guillem Jover <guillem@...rons.org>,
libc-alpha@...rceware.org, musl@...ts.openwall.com,
libbsd@...ts.freedesktop.org, "Serge E. Hallyn" <serge@...lyn.com>,
"Skyler Ferrante (RIT Student)" <sjf5462@....edu>,
Iker Pedrosa <ipedrosa@...hat.com>,
Christian Brauner <christian@...uner.io>
Subject: Re: Re: Tweaking the program name for <err.h> functions
Hi Rich,
On Sun, Mar 10, 2024 at 03:39:56PM -0400, Rich Felker wrote:
> Also, the whole reason this comes up is gratuitous impedance mismatch
> bringing in the need for a separate fprintf call to do the prefix (and
> possibly newline suffix, if you want that). They could have been
> designed to be one-line macros, ala...
>
> #define warn(f,...) fprintf(stderr, "%s: " f, __progname, __VA_ARGS__)
>
> or similar.
Hmmm, it's an interesting definition. That's actually warnx(3), but you
can write the others in terms of that:
#define setprogname(n) do { program_invocation_short_name = n; } while (0)
#define getprogname() (program_invocation_short_name)
#define warnx(f, ...) fprintf(stderr, "%s: " f "\n", getprogname(), ##__VA_ARGS__)
#define warnc(c, f, ...) warnx(f ": %s", ##__VA_ARGS__, strerror(c))
#define warn(f, ...) warnc(errno, f, ##__VA_ARGS__)
#define errx(x, ...) do { warnx(__VA_ARGS__); exit(x); } while (0)
#define errc(x, ...) do { warnc(__VA_ARGS__); exit(x); } while (0)
#define err(x, ...) do { warn(__VA_ARGS__); exit(x); } while (0)
The main problem is still portability. But I guess with some cpp(1)
I can get it to work in the systems I care about.
libc couldn't implement it this way, because complex things like "%2ms"
wouldn't work. But it could be interesting in a multi-threaded program,
where such complex conversion specifications don't occur.
Still, that's not my case. I guess I'll do this:
#if (!WITH_LIBBSD)
inline void
setprogname(const char *progname)
{
program_invocation_short_name = Basename(name);
}
inline const char *
getprogname(void)
{
return program_invocation_short_name;
}
#endif
> I really see no justifiable reason for people writing new
> software to want to enhance the err.h functions rather than just
I don't really need to enhance them. Just a statement that the current
behavior will hold would be good enough. I would need to know that
setting 'program_invocation_short_name' will set the prefix of these
functions. That's already the current behavior, and I guess that you'll
keep it, even if just for backwards compatibility; more so, considering
your aversion to fix or break these APIs, or to change them at all.
> rolling a one-line macro that can be better tailored to their specific
> needs.
>
> Rich
Have a lovely night!
Alex
--
<https://www.alejandro-colomar.es/>
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