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Date: Tue, 21 Jul 2020 18:56:57 +0200
From: Markus Wichmann <>
Subject: Re: perhaps we should add re[c]allocarray?

On Tue, Jul 21, 2020 at 04:18:35AM -0600, Ariadne Conill wrote:
> Hello,
> reallocarray and recallocarray are BSD extensions that solve similar issues as
> strlcpy/strlcat, but with array reallocations instead of strings.
> reallocarray itself is already part of glibc since 2.28.
> Unfortunately, while working on new ifupdown implementation for Alpine, I
> wanted to use recallocarray because it is very helpful in terms of pushing new
> strings to a string array (you will always maintain a NULL-terminated array,
> and you don't have to worry about it) -- but I discovered musl still does not
> have it.
> Anyway, I think it would be useful to include both functions in musl 1.2.1.
> If everyone agrees, I'll make a patch.
> Ariadne

Seems mostly useless to me. reallocarray() is equivalent to realloc(),
multiplying the last two arguments. And recallocarray() does seem
useful, but moreso as a subroutine. I see little reason to put this into
a standard library.

On a formal point of view, neither of these has been standardized. I can
find an Oracle man page for reallocarray(), but not recallocarray().
Both are OpenBSD extensions. For glibc, I can find reallocarray() (which
mostly wraps realloc()), but no recallocarray() (I checked in the most
recent released version, which is 2.31 as of right now).

It appears, reallocarray() enjoys more widespread adoption than
recallocarray(). Both can, however, be easily found by a compile/link
test. As stated above, however, the necessary functionality can easily
be written in whatever application needs it, so I don't see the point.
I've done that before; it is two lines if you manage your variables


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