srand(n) - phpMan

srand (3)            - pseudo-random number generator
srand (3p)           - pseudo-random number generator
srand48 (3)          - generate uniformly distributed pseudo-random numbers
srand48 (3p)         - generate uniformly distributed pseudo-random numbers
srand48_r (3)        - generate uniformly distributed pseudo-random numbers r...
srandom (3)          - random number generator
srandom (3p)         - pseudo-random number functions
srandom_r (3)        - reentrant random number generator