## Description

`int `**mt_rand**

([int min [, int max]])

Many random number generators of older libcs have dubious or unknown characteristics and are slow. By default, PHP uses the libc random number generator with the **rand()** function. **mt_rand()** function is a drop-in replacement for this. It uses a random number generator with known characteristics, the Mersenne Twister, which will produce random numbers that should be suitable for seeding some kinds of cryptography (see the home pages for details) and is four times faster than what the average libc provides. The Homepage of the Mersenne Twister can be found at http://www.math.keio.ac.jp/~matumoto/emt.html, and an optimized version of the MT source is available from http://www.scp.syr.edu/~marc/hawk/twister.html .

If called without the optional *min*, *max* arguments **mt_rand()** returns a pseudo-random value between 0 and `RAND_MAX`. If you want a random number between 5 and 15 (inclusive), for example, use `mt_rand (5, 15)`.

Remember to seed the random number generator before use with **mt_srand()**.

**Note: ** In versions before 3.0.7 the meaning of *max* was *range*. To get the same results in these versions the short example should be `mt_rand (5, 11)` to get a random number between 5 and 15.

See also **mt_srand()**, **mt_getrandmax()**, **srand()**, **rand()** and **getrandmax()**.