srand(3) [php man page]

SRAND(3)								 1								  SRAND(3)

srand - Seed the random number generator

SYNOPSIS

       void srand ([int  $seed])

DESCRIPTION

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

       Note

	      As  of  PHP  4.2.0,  there is no need to seed the random number generator with srand(3) or mt_srand(3) as this is now done automati-
	      cally.

PARAMETERS

	      o $seed
		- Optional seed value

RETURN VALUES

	No value is returned.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 4.2.0	|						    |
       |	|						    |
       |	|  The $seed becomes optional  and  defaults  to  a |
       |	| random value if omitted.			    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	      srand(3) example

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

SEE ALSO

       rand(3), getrandmax(3), mt_srand(3).

PHP Documentation Group 														  SRAND(3)

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).

PHP Documentation Group 													       MT_SRAND(3)