NAME

rand, srand − random number generator

SYNOPSIS

srand(seed)
int seed;

rand()

DESCRIPTION

Rand uses a multiplicative congruential random number generator with period 232 to return successive pseudo-random numbers in the range from 0 to 231−1. 

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. 

BUGS

Rand does not provide mutual exclusion among calling processes.  Thus, there is a small chance that two concurrent processes will receive the same value. 

December 01, 1986  —  Xinu Programmer’s Manual