Something puzzling me in PHP

rand() function

[sugarkane]

A while ago I pinched a snippet of PHP from somewhere to use in a session id generator. It all worked fine, but as I was only just starting out in PHP I didn't investigate too deeply how it worked. This construct is now puzzling me:

$foo=rand()%(strlen($pool));

The effect is to choose a random number between zero and the character length of string $pool - yet I can't find any documentation on this form of rand() anywhere... the manual for PHP4 specifies rand(min_value, max_value) for this kind of thing.

Does anyone know if this is a correct construct or a hangover from an earlier version of PHP?

[Froggyman]

It's not a hangover. If no seed value is provided, the rand() function is automatically seeded with a value of 1.

[sugarkane]

Thanks Froggyman. It's the % sign that puzzles me - I take it this is just a different method of specifying the maximum value?