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)
