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 all systems, if the environment variable B<RANDFILE> is set, its
24 value will be used as the seed file name.
26 Otherwise, the file is called ".rnd", found in platform dependent locations:
30 =item On Windows (in order of preference)
32 %HOME%, %USERPROFILE%, %SYSTEMROOT%, C:\
38 =item On all other systems
44 If C<$HOME> (on non-Windows and non-VMS system) is not set either, or
45 B<num> is too small for the path name, an error occurs.
47 RAND_load_file() reads a number of bytes from file B<filename> and
48 adds them to the PRNG. If B<max_bytes> is non-negative,
49 up to B<max_bytes> are read;
50 if B<max_bytes> is -1, the complete file is read.
52 RAND_write_file() writes a number of random bytes (currently 1024) to
53 file B<filename> which can be used to initialize the PRNG by calling
54 RAND_load_file() in a later session.
58 RAND_load_file() returns the number of bytes read.
60 RAND_write_file() returns the number of bytes written, and -1 if the
61 bytes written were generated without appropriate seed.
63 RAND_file_name() returns a pointer to B<buf> on success, and NULL on
68 L<rand(3)>, L<RAND_add(3)>, L<RAND_cleanup(3)>
72 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
74 Licensed under the OpenSSL license (the "License"). You may not use
75 this file except in compliance with the License. You can obtain a copy
76 in the file LICENSE in the source distribution or at
77 L<https://www.openssl.org/source/license.html>.