mt_srand Seeds the Mersenne Twister Random Number Generator &reftitle.description; voidmt_srand intseed intmodeMT_RAND_MT19937 Seeds the random number generator with seed or with a random value if no seed is given. ¬e.randomseed; &reftitle.parameters; seed An arbitrary integer seed value. mode Use one of the following constants to specify the implementation of the algorithm to use. Constant &Description; MT_RAND_MT19937 Uses the fixed, correct, Mersenne Twister 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. &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. 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 nonetheless. &reftitle.examples; ]]> &reftitle.seealso; mt_rand mt_getrandmax srand