RAND(3) Library Functions Manual RAND(3)
rand, srand - random number generator
Rand uses a multiplicative congruential random number generator with
period 232 to return successive pseudo-random numbers in the range from
0 to 215-1.
The generator is reinitialized by calling srand with 1 as argument. It
can be set to a random starting point by calling srand with whatever
you like as argument.