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Date: Sun, 12 Apr 2015 21:36:04 +0200
To: =?utf-8?Q?Leszek_Krupi=C5=84ski?= <internals@lists.php.net>
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Subject: $max > getmaxrand() for rand() call
From: leafnode@gmail.com (Leszek Krupinski)

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Hello

A friend of mine reported something that seemed like a bug =
(https://bugs.php.net/bug.php?id=3D69396 =
<https://bugs.php.net/bug.php?id=3D69396>) - to sum up: if you provide =
$max parameter that is larger than OS-provided getmaxrand(), the result =
will be artificially stretched, which in result leads to some values not =
appearing at all. That=E2=80=99s troublesome if for instance some people =
use that function to choose random server for a service, and the =
stretched result wouldn=E2=80=99t return even values at all.

The very same thing is reported as a first comment for the rand() =
function in PHP manual - and that comment is 8 years old.

Apparently this is a sort-of correct behaviour, but it should be taken =
care of. I see 4 ways:
1. Document the behaviour and keep it that way.
2. Allow that behaviour, document it, but if $max > getrandmax(), emit a =
warning/notice.
3. Disallow that, document, and return false (as some other functions do =
when arguments are incorrect).
4. Disallow that, but trim $max to getrandmax(), and emit a =
warning/notice.

I think that this behaviour should not be allowed, because in the end it =
generates incorrect results, doesn=E2=80=99t matter if the user would =
like that or not.

What do you think about this issue?

=E2=80=94Leszek=

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