drand(3f) [bsd man page]

RAND(3F)																  RAND(3F)

NAME

       rand, drand, irand - return random values

SYNOPSIS

       function irand (iflag)

       function rand (iflag)

       double precision function drand (iflag)

DESCRIPTION

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

       These  functions  use  rand(3C)	to generate sequences of random numbers.  If iflag is '1', the generator is restarted and the first random
       value is returned.  If iflag is otherwise non-zero, it is used as a new seed for the random number generator,  and  the	first  new  random
       value is returned.

       Irand returns positive integers in the range 0 through 2147483647.  Rand and drand return values in the range 0. through 1.0 .

FILES

       /usr/lib/libF77.a

SEE ALSO

       random(3F), rand(3C)

BUGS

       The  algorithm  returns a 15 bit quantity on the PDP11; a 31 bit quantity on the VAX.  Irand on the PDP11 calls rand(3C) twice to form a 31
       bit quantity, but bit 15 will always be 0.

4.2 Berkeley Distribution					   May 15, 1985 							  RAND(3F)

rand(3UCB)					     SunOS/BSD Compatibility Library Functions						rand(3UCB)

NAME

       rand, srand - simple random number generator

SYNOPSIS

       /usr/ucb/cc [ flag ... ] file ...

       int rand();

       int srand(seed)
       unsigned seed;

DESCRIPTION

       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.

       srand() 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.

SEE ALSO

       cc(1B), drand48(3C), rand(3C), random(3C)

NOTES

       Use of these interfaces should be restricted to only applications written on BSD platforms.  Use of these interfaces with any of the system
       libraries or in multi-thread applications is unsupported.

       The spectral properties of rand() leave a great deal to be desired. drand48(3C) and random(3C) provide much better, though more	elaborate,
       random-number generators.

       The low bits of the numbers generated are not very random; use the middle bits. In particular the lowest bit alternates between 0 and 1.

SunOS 5.11							    30 Oct 2007 							rand(3UCB)