NAME
rand,
srand,
rand_r
—
bad random number generator
LIBRARY
Standard C Library (libc, -lc)
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
random(3),
rnd(4)
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”).