NAME
getentropy —
get entropy
SYNOPSIS
#include
<unistd.h>
int
getentropy(void
*buf, size_t
buflen);
DESCRIPTION
getentropy fills a buffer with
high-quality entropy, which can be used as input for process-context
pseudorandom generators like
arc4random(3).
The maximum buffer size permitted is 256 bytes. If
buflen exceeds this, an error of
EIO will be indicated.
getentropy is not intended for regular
code; please use the
arc4random(3) family of functions instead.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.
ERRORS
getentropy() will succeed unless:
- [
EFAULT] - The buf parameter points to an invalid address.
- [
EIO] - Too many bytes requested, or some other fatal error occurred.
SEE ALSO
HISTORY
The getentropy function appeared in
OpenBSD 5.6.