opendarwin man page for rand_bytes

RAND_bytes(3)							      OpenSSL							     RAND_bytes(3)

NAME
       RAND_bytes, RAND_pseudo_bytes - generate random data

SYNOPSIS
	#include <openssl/rand.h>

	int RAND_bytes(unsigned char *buf, int num);

	int RAND_pseudo_bytes(unsigned char *buf, int num);

DESCRIPTION
       RAND_bytes() puts num cryptographically strong pseudo-random bytes into buf. An error occurs if the PRNG has not been seeded with enough
       randomness to ensure an unpredictable byte sequence.

       RAND_pseudo_bytes() puts num pseudo-random bytes into buf.  Pseudo-random byte sequences generated by RAND_pseudo_bytes() will be unique if
       they are of sufficient length, but are not necessarily unpredictable. They can be used for non-cryptographic purposes and for certain pur-
       poses in cryptographic protocols, but usually not for key generation etc.

RETURN VALUES
       RAND_bytes() returns 1 on success, 0 otherwise. The error code can be obtained by ERR_get_error(3). RAND_pseudo_bytes() returns 1 if the
       bytes generated are cryptographically strong, 0 otherwise. Both functions return -1 if they are not supported by the current RAND method.

SEE ALSO
       rand(3), ERR_get_error(3), RAND_add(3)

HISTORY
       RAND_bytes() is available in all versions of SSLeay and OpenSSL.  It has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added
       in OpenSSL 0.9.5.

0.9.7d								    2003-11-20							     RAND_bytes(3)