GETENTROPY(3) | Library Functions Manual | GETENTROPY(3) |
getentropy
—
#include <unistd.h>
int
getentropy
(void
*buf, size_t
buflen);
#include
<limits.h>
#define
GETENTROPY_MAX 256
getentropy
() function fills a buffer with high
quality random data, suitable for seeding cryptographically secure
psuedorandom number generators.
getentropy
() is only intended for seeding
random number generators and is not intended for use by regular code which
simply needs secure random data. For this purpose, please use
arc4random(3).
The maximum value for buflen
is 256
bytes.
getentropy
() reads from the
sysctl(7) variable
kern.arandom
.
getentropy
() function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
getentropy
() will succeed unless:
getentropy
() function is non-standard. However, it
is likely to be included in the next revision of POSIX.
getentropy
() function first appeared in
OpenBSD 5.6, then in FreeBSD
12.0, and NetBSD 10.
May 1, 2020 | NetBSD 10.0 |