mt_srand

Seeds the Mersenne Twister Random Number Generator

&reftitle.description; `void` `mt_srand` `int` `seed` 0 `int` `mode` `MT_RAND_MT19937`

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

¬e.randomseed; &caution.mt19937-tiny-seed;
&reftitle.parameters;

`seed`

- An arbitrary `int` seed value.

`mode`

- Use one of the following constants to specify the implementation of the algorithm to use.

  - `MT_RAND_MT19937`: The correct Mt19937 implementation, available as of PHP 7.1.0.
  - `MT_RAND_PHP` Uses an incorrect Mersenne Twister implementation which was used as the default up till PHP 7.1.0. This mode is available for backward compatibility.
  &warn.deprecated.feature-8-3-0;
&reftitle.returnvalues;

&return.void;

&reftitle.changelog;

&Version; | &Description;
7.1.0 | `srand` has been made an alias of `mt_srand`.
7.1.0 | `mt_rand` has been updated to use the fixed, correct, version of the Mersenne Twister algorithm. To fall back to the old behaviour, use `mt_srand` with `MT_RAND_PHP` as the second parameter.

&reftitle.seealso;

- `mt_rand`
- `mt_getrandmax`
- `srand`