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mt_srand

PHP function Edit on GitHub ✎

(PHP 4, PHP 5, PHP 7, PHP 8)

Seeds the Mersenne Twister Random Number Generator

Description

mt_srand(int|null $seed = null, int $mode = MT_RAND_MT19937): void

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

Randomseed Mt19937-tiny-seed

seed

Fills the state with values generated with a linear congruential generator that was seeded with seed interpreted as an unsigned 32 bit integer.

If seed is omitted or null, a random unsigned 32-bit integer will be used.

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.

Feature-8-3-0

Void

Version	Description
8.3.0	`seed` is now nullable.
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.