srand and mt_srand are both initialized only once per process ID.
You cannot re-seed your rand algorithms after the first "srand", "mt_srand", "rand", "mt_rand", "shuffle", or any other rand-like function.
I have been facing an issue where after forking my process, all childs were generating exactly the same rand values.
This was due a first "shuffle" call on the parent process, so I could not re-seed the childs.
To solve my issue, I simple called "rand" N times, to offset the child rand generators.
# Offset the child rand generator by its PID
$n = (getmypid() % 100) * (10 * abs(microtime(true) - time()));
for ($n; $n > 0; $n--) {
rand(0, $n);
}
Since each pcntl_fork takes a while to be completed, the microtime offers an extra offset, other than one PID increment.
This small code will make at the WORST hypothesis 1000 iterations.
