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From: Szabolcs Nagy <nsz@port70.net>
To: Ed Schouten <ed@nuxi.nl>
Cc: musl@lists.openwall.com
Subject: Re: jrand48(): missing cast to int32_t?
Date: Fri, 9 Dec 2016 18:05:13 +0100	[thread overview]
Message-ID: <20161209170512.GD16379@port70.net> (raw)
In-Reply-To: <CABh_MKm9w3uXtQx4zHS1mOLLFK7=RViX86+DNtYmrNFr_8C+qQ@mail.gmail.com>

* Ed Schouten <ed@nuxi.nl> [2016-12-09 07:16:42 +0100]:
> According to POSIX, jrand48() is supposed to return a value between
> [-2^31, 2^31). Musl's version of jrand48() is implemented as follows:
> 
> long jrand48(unsigned short s[3])
> {
>         return __rand48_step(s, __seed48+3) >> 16;
> }

nice catch, note that posix does not guarantee that
long can represent -2^31 so this requirement is not
possible to implement portably (indeed your proposed
cast has implementation defined effect, but in musl
we already rely on it to work as expected).

i submitted a posix bug report against limits.h
http://austingroupbugs.net/view.php?id=1108


      reply	other threads:[~2016-12-09 17:05 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-09  6:16 Ed Schouten
2016-12-09 17:05 ` Szabolcs Nagy [this message]

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