|RAND(3)||Library Functions Manual||RAND(3)|
To satisfy portable code,
srand() may be
called to initialize the subsystem. In OpenBSD the
seed variable is ignored, and strong random number
results will be provided from
arc4random(3). In other systems, the
seed variable primes a simplistic deterministic
If the standardized behavior is required
srand_deterministic() can be substituted for
srand(), then subsequent
rand() calls will return results using the
rand() function returns a result in
the range of 0 to
RAND_MAX. By default, this result
comes from arc4random(3). If
srand_deterministic() was called, the result will be
computed using the deterministic algorithm.
rand_r() is a thread-safe version of
rand(). Storage for the seed must be provided
through the seed argument, and needs to have been
initialized by the caller. It always operates using the deterministic
rand() function conforms to ANSI X3.159-1989 (“ANSI C89”).
rand_r() function conforms to
IEEE Std 1003.1-2008 (“POSIX.1”).
srand() function does not conform to
ANSI X3.159-1989 (“ANSI C89”),
srand_deterministic() function is an
srand() first appeared in Version 3 AT&T UNIX.
|December 9, 2014||OpenBSD-current|