srand(3c) [bsd man page]

RAND(3C)																  RAND(3C)

NAME

       rand, srand - random number generator

SYNOPSIS

       srand(seed)
       int seed;

       rand()

DESCRIPTION

       The newer random(3) should be used in new applications; rand remains for compatibilty.

       Rand  uses  a multiplicative congruential random number generator with period 2**32 to return successive pseudo-random numbers in the range
       from 0 to (2**31)-1 on the VAX, and (2**15)-1 on the PDP-11.

       The generator is reinitialized by calling srand with 1 as argument.  It can be set to a random starting point by calling srand  with  what-
       ever you like as argument.

SEE ALSO

       random(3)

7th Edition							September 29, 1985							  RAND(3C)

RAND(3) 						   BSD Library Functions Manual 						   RAND(3)

NAME

     rand, rand_r, srand, sranddev -- bad random number generator

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <stdlib.h>

     int
     rand(void);

     int
     rand_r(unsigned *seed);

     void
     srand(unsigned seed);

     void
     sranddev(void);

DESCRIPTION

     These interfaces are obsoleted by arc4random(3).

     The rand() function computes a sequence of pseudo-random integers in the range of 0 to RAND_MAX (as defined by the header file <stdlib.h>).

     The srand() function sets its argument seed as the seed for a new sequence of pseudo-random numbers to be returned by rand().  These
     sequences are repeatable by calling srand() with the same seed value.

     If no seed value is provided, the functions are automatically seeded with a value of 1.

     The sranddev() function initializes a seed, using the random(4) random number device which returns good random numbers.  However, the rand()
     function still remains unsuitable for cryptographic use.

     The rand_r() function provides the same functionality as rand().  A pointer to the context value seed must be supplied by the caller.

SEE ALSO

     arc4random(3), random(3), random(4)

STANDARDS

     The rand() and srand() functions conform to ISO/IEC 9899:1990 (``ISO C90'').

     The rand_r() function is as proposed in the POSIX.4a Draft #6 document.

BSD
								   May 25, 1999 							       BSD