How to get the seed value from a random number generator in PHP

Question

I would like to get the seed value after the rand() or mt_rand() is used. Essentially I want to store the seed so that I can use this seed to continue generating random numbers next time php is executed.

I need a repeatable behavior for unit testing/load testing... and different modules in my applications will use the same seed, so that the sequence of random numbers are generated are reproducible.

Thanks for your input. I couldn't find a method to get the seed. A Random number generator class that exposes the seed would be helpful too.

Answer 1

If you need repeatable behavior, you should seed rand() or mt_rand() yourself using srand() or mt_srand() and store the seed that you use.

Answer 2

AFAIK the only way to know what the seed in use is is to specify it yourself.

Answer 3

mt_srand($known_value)

Will set your seed to a repeatable value