5 RAND_load_file, RAND_write_file, RAND_file_name - PRNG seed file
9 #include <openssl/rand.h>
11 const char *RAND_file_name(char *buf, size_t num);
13 int RAND_load_file(const char *filename, long max_bytes);
15 int RAND_write_file(const char *filename);
19 RAND_file_name() generates a default path for the random seed
20 file. B<buf> points to a buffer of size B<num> in which to store the
23 On Windows the seed file is %RANDFILE% if that environment variable is set.
24 Otherwise the file is called ".rnd" in one of the following locations (in order
25 of preference): %TMP%, %TEMP%, %USERPROFILE%, %SYSTEMROOT%, %HOME%, "C:".
27 On all other systems the seed file is $RANDFILE if that environment variable is
28 set, $HOME/.rnd otherwise.
30 If $HOME (on non Windows systems) is not set either, or B<num> is
31 too small for the path name, an error occurs.
33 RAND_load_file() reads a number of bytes from file B<filename> and
34 adds them to the PRNG. If B<max_bytes> is non-negative,
35 up to B<max_bytes> are read;
36 if B<max_bytes> is -1, the complete file is read.
38 RAND_write_file() writes a number of random bytes (currently 1024) to
39 file B<filename> which can be used to initialize the PRNG by calling
40 RAND_load_file() in a later session.
44 RAND_load_file() returns the number of bytes read.
46 RAND_write_file() returns the number of bytes written, and -1 if the
47 bytes written were generated without appropriate seed.
49 RAND_file_name() returns a pointer to B<buf> on success, and NULL on
54 L<rand(3)>, L<RAND_add(3)>, L<RAND_cleanup(3)>
58 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
60 Licensed under the OpenSSL license (the "License"). You may not use
61 this file except in compliance with the License. You can obtain a copy
62 in the file LICENSE in the source distribution or at
63 L<https://www.openssl.org/source/license.html>.