Random routines

Never, ever, ever, and I mean it, use

rand + srand

random + srandom

erand / drand48 + srand48
nrand / lrand48 + seed48
jrand / mrand48 + lcong48

Instead
read /dev/random if you need really strong random numbers
read /dev/urandom if you need good pseudo random numbers
use the OpenSSL library's RAND_bytes/RAND_pseudo_bytes if you want to be lazy