Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for initstate (redhat section 3)

RANDOM(3)			    Linux Programmer's Manual				RANDOM(3)

NAME
       random, srandom, initstate, setstate - random number generator.

SYNOPSIS
       #include <stdlib.h>

       long int random(void);
       void srandom(unsigned int seed);
       char *initstate(unsigned int seed, char *state, size_t n);
       char *setstate(char *state);

DESCRIPTION
       The  random() function uses a non-linear additive feedback random number generator employ-
       ing a default table of size 31 long integers to return successive pseudo-random numbers in
       the  range  from 0 to RAND_MAX.	The period of this random number generator is very large,
       approximately 16*((2**31)-1).

       The srandom() function sets its argument as the seed for a new sequence	of  pseudo-random
       integers  to be returned by random().  These sequences are repeatable by calling srandom()
       with the same seed value.  If no seed value is provided, the random() function is automat-
       ically seeded with a value of 1.

       The initstate() function allows a state array state to be initialized for use by random().
       The size of the state array n is used by initstate() to decide how sophisticated a  random
       number  generator  it should use -- the larger the state array, the better the random num-
       bers will be.  seed is the seed for the initialization, which specifies a  starting  point
       for the random number sequence, and provides for restarting at the same point.

       The  setstate() function changes the state array used by the random() function.	The state
       array state is used for random number generation until the next	call  to  initstate()  or
       setstate().   state must first have been initialized using initstate() or be the result of
       a previous call of setstate().

RETURN VALUE
       The random() function returns a value between 0	and  RAND_MAX.	 The  srandom()  function
       returns no value.  The initstate() and setstate() functions return a pointer to the previ-
       ous state array, or NULL on error.

ERRORS
       EINVAL A state array of less than 8 bytes was specified to initstate().

NOTES
       Current "optimal" values for the size of the state array n are 8, 32,  64,  128,  and  256
       bytes;  other amounts will be rounded down to the nearest known amount.	Using less than 8
       bytes will cause an error.

CONFORMING TO
       BSD 4.3

SEE ALSO
       rand(3), srand(3)

GNU					    2000-08-20					RANDOM(3)


All times are GMT -4. The time now is 01:08 PM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password