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random(3M)							    random(3M)

       random(),  srandom(), initstate(), setstate() - generate a pseudorandom

       The and functions are random-number generators that have virtually  the
       same  calling  sequence	and initialization properties as the and func‐
       tions, but produce sequences that are more random.   The	 low  12  bits
       generated  by  the  function go through a cyclic pattern, while all the
       bits generated by the function are usable.   For	 example,  produces  a
       random binary value.

       The function uses a nonlinear additive feedback random-number generator
       employing a default state array size of 31 long integers to return suc‐
       cessive	pseudorandom numbers in the range from 0 to The period of this
       random-number generator is approximately 16 x The  size	of  the	 state
       array determines the period of the random-number generator.  Increasing
       the state array size increases the period.

       With 256 bytes of state information, the period	of  the	 random-number
       generator is greater than

       Like  the function, the function produces by default a sequence of num‐
       bers that can be duplicated by calling the function with a value	 of  1
       as the seed.

       The  function  initializes  the	current state array using the value of

       The and functions handle restarting and changing random-number  genera‐
       tors.  The function allows a state array, pointed to by the state argu‐
       ment, to be initialized for future use.	The size argument, which spec‐
       ifies  the size in bytes of the state array, is used by the function to
       decide how sophisticated a random-number generator to use;  the	larger
       the state array, the more random the numbers.  Values for the amount of
       state information are 8, 32, 64, 128, and 256 bytes.  Amounts less than
       8  bytes return a NULL pointer, while other amounts are rounded down to
       the nearest known value.	 The seed argument specifies a starting	 point
       for  the random-number sequence and provides for restarting at the same
       point.  The function returns a pointer to the previous  state  informa‐
       tion array.

       Once  a	state  has  been  initialized,	the  function allows switching
       between state arrays.  The array defined by the state argument is  used
       for  further  random-number  generation until the function is called or
       the function is called again.  The function returns a  pointer  to  the
       previous state array.

       After  initialization,  a  state	 array can be restarted at a different
       point in one of two ways:

	      The function can be used, with the desired  seed,	 state	array,
	      and size of the array.

	      The  function,  with the desired state, can be used, followed by
	      the function with the desired seed.  The advantage of using both
	      of  these functions is that the size of the state array does not
	      have to be saved once it is initialized.

       The function returns the generated pseudorandom number.

       The function returns no value.

       Upon successful completion, the and functions return a pointer  to  the
       previous state array.  Otherwise, a NULL pointer is returned.

       If  the	function  detects that the state information has been damaged,
       error messages are written to standard error.

       drand48(3C), rand(3C), random(7).


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