RAND(2)                                                   RAND(2)

     NAME
          rand, lrand, frand, nrand, lnrand, srand - random number
          generator

     SYNOPSIS
          #include <u.h>
          #include <libc.h>

          int    rand(void)

          long   lrand(void)

          double frand(void)

          int    nrand(int val)

          long   lnrand(long val)

          void   srand(long seed)

     DESCRIPTION
          Rand returns a uniform pseudo-random number x, 0≤x<215.

          Lrand returns a uniform long x, 0≤x<231.

          Frand returns a uniform double x, 0.0≤x<1.0, This function
          calls lrand twice to generate a number with as many as 62
          significant bits of mantissa.

          Nrand returns a uniform integer x, 0≤x<val.  Lnrand is the
          same, but returns a long.

          The algorithm is additive feedback with:

               x[n] = (x[n-273] + x[n-607]) mod 2^31

          giving a period of 2^30 × (2^607 - 1).

          The generators are initialized by calling srand with what-
          ever you like as argument.  To get a different starting
          value each time,

               srand(time(0))

          will work as long as it is not called more often than once
          per second.  Calling

               srand(1)

          will initialize the generators to their starting state.

     Page 1                       Plan 9             (printed 3/29/24)

     RAND(2)                                                   RAND(2)

        Alef
          There is no rand in Alef.

     SOURCE
          /sys/src/libc/port/rand.c

     Page 2                       Plan 9             (printed 3/29/24)