php man page for mt_srand

MT_SRAND(3)								 1							       MT_SRAND(3)

mt_srand - Seed the better random number generator

SYNOPSIS
       void mt_srand ([int  $seed])

DESCRIPTION
	Seeds the random number generator with $seed or with a random value if no $seed is given.

       Note

	      There is no need to seed the random number generator with srand(3) or mt_srand(3) as this is done automatically.

PARAMETERS
	      o $seed
		- An optional seed value

RETURN VALUES
	No value is returned.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.2.1	|						    |
       |	|						    |
       |	|  The	Mersenne  Twister implementation in PHP now |
       |	| uses a new seeding algorithm by  Richard  Wagner. |
       |	| Identical   seeds  no  longer  produce  the  same |
       |	| sequence of values they did in previous versions. |
       |	| This	behavior  is  not expected to change again, |
       |	| but it is considered unsafe to rely upon it none- |
       |	| theless.					    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      mt_srand(3) example

	      <?php
	      // seed with microseconds
	      function make_seed()
	      {
		list($usec, $sec) = explode(' ', microtime());
		return (float) $sec + ((float) $usec * 100000);
	      }
	      mt_srand(make_seed());
	      $randval = mt_rand();
	      ?>

SEE ALSO
       mt_rand(3), mt_getrandmax(3), srand(3).

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