NAME
rand, srand,
rand_r —
bad random number generator
LIBRARY
library “libc”
SYNOPSIS
#include
<stdlib.h>
void
srand(unsigned
int seed);
int
rand(void);
int
rand_r(unsigned
int *seed);
DESCRIPTION
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 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
rand()
function is automatically seeded with a value of 1.
The
rand_r()
function is a reentrant interface to rand(); the
seed has to be supplied and is maintained by the caller.
SEE ALSO
STANDARDS
The rand() and
srand() functions conform to ANSI
X3.159-1989 (“ANSI C89”). The
rand_r() function conforms to IEEE
Std 1003.1c-1995 (“POSIX.1c”).