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Message-ID: <20161209170512.GD16379@port70.net>
Date: Fri, 9 Dec 2016 18:05:13 +0100
From: Szabolcs Nagy <nsz@...t70.net>
To: Ed Schouten <ed@...i.nl>
Cc: musl@...ts.openwall.com
Subject: Re: jrand48(): missing cast to int32_t?

* Ed Schouten <ed@...i.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

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