drandm(3f) [bsd man page]

RANDOM(3F)																RANDOM(3F)

NAME

       random, drandm, irandm - better random number generator

SYNOPSIS

       function irandm (iflag)

       function random (iflag)

       double precision function drandm (iflag)

DESCRIPTION

       These  functions use random(3) to generate sequences of random numbers, and should be used rather than the older functions described in man
       3f rand.  If iflag is non-zero, it is used as a new seed for the random number generator, and the first new random value is returned.

       Irandm returns positive integers in the range 0 through 2147483647 ( 2**31-1).  Random and drandm return values in the range 0. through 1.0
       by dividing the integer random number from random(3) by 2147483647 .

FILES

       /usr/lib/libF77.a

SEE ALSO

       random(3)

4.3 Berkeley Distribution					   May 15, 1985 							RANDOM(3F)

rand(3C)																  rand(3C)

NAME

       rand(), rand_r(), srand() - simple random-number generator

SYNOPSIS

DESCRIPTION

       uses  a	multiplicative,  congruential, random-number generator with period 2^32 that returns successive pseudo-random numbers in the range
       from 0 to 2^15-1.

       can be called at any time to reset the random-number generator to a random starting point.  The generator is initially seeded with a  value
       of 1.

       returns a random number at the address pointed to by the randval parameter.  The seed parameter can be set at any time to start the random-
       number generator at an arbitrary point.

   Note
       The spectral properties of leave a great deal to be desired.  provides a much better, though more elaborate, random-number  generator  (see
       drand48(3C)).

RETURN VALUE

       If seed or randval is NULL, returns 0.  Otherwise, returns a psuedo-random integer.

EXAMPLES

       The following:

	      int x, y;
	      srand(10);
	      x = rand();
	      y = rand();

       would produce the same results as:

	      int x, y, s = 10;
	      x=rand_r(&s);
	      y=rand_r(&s);

WARNINGS

       Users  of  should  note	that  rand_r()	now conforms with POSIX.1c.  The old prototype of is supported for compatibility with existing DCE
       applications only.

SEE ALSO

       drand48(3C), random(3M), thread_safety(5), random(7).

STANDARDS CONFORMANCE

																	  rand(3C)