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Message-ID: <20200823102439.2bbaffb5@inria.fr>
Date: Sun, 23 Aug 2020 10:24:39 +0200
From: Jens Gustedt <jens.gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: direct coding of asctime_r

Hello,
I don't know if you guys noticed, but sometime ago we voted some of
the ..._r functions from <time.h> into the C standard, just to then
discover that POSIX has deprecated the whole set of functions and
proposes to replace them by `strftime`.

One of the arguments to keep them, was that `asctime_r` does not need
access to locale and has a fixed format, and so can be implemented
with a much smaller footprint.

Looking into musl I found that the current implementation is basically
doing verbatim what the C standard says, namely uses `snprintf` under
the hood to do the formatting. This has obviously the disadvantage
that this drags the whole infrastructure that is needed for `snprintf`
into the executable.

Making some tests, I found that coding `asctime_r` straight forward
with byte-copying has it shave off about 10k from the final
executable.

Would it be interesting for musl to change to such an implementation?

Shall I prepare a patch to do so?

Jens

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