Description

   The rand function computes a sequence of pseudorandom integers in
   the range 0 to {RAND_MAX} with a period of at least 2[32].

   The rand_r function computes a sequence of pseudorandom integers
   in the range 0 to {RAND_MAX}. The value of the {RAND_MAX} macro
   will be at least 32767.

   If rand_r is called with the same initial value for the object
   pointed to by seed and that object is not modified between
   successive returns and calls to rand_r, the same sequence is
   generated.

   See also srand.

   For other random-number algorithms, see random and all the *48
   functions.