.\"	$OpenBSD: RAND_load_file.3,v 1.6 2018/03/27 17:35:50 schwarze Exp $
.\"	OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
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.\" This file was written by Ulf Moeller <ulf@openssl.org>.
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.Dd $Mdocdate: March 27 2018 $
.Dt RAND_LOAD_FILE 3
.Os
.Sh NAME
.Nm RAND_file_name ,
.Nm RAND_load_file ,
.Nm RAND_write_file
.Nd PRNG seed file
.Sh SYNOPSIS
.In openssl/rand.h
.Ft const char *
.Fo RAND_file_name
.Fa "char *buf"
.Fa "size_t num"
.Fc
.Ft int
.Fo RAND_load_file
.Fa "const char *filename"
.Fa "long max_bytes"
.Fc
.Ft int
.Fo RAND_write_file
.Fa "const char *filename"
.Fc
.Sh DESCRIPTION
.Fn RAND_file_name
returns a default path for the random seed file.
.Fa buf
points to a buffer of size
.Fa num
in which to store the filename.
If
.Fa num
is too small for the path name, an error occurs.
.Pp
.Fn RAND_load_file
used to allow for the state of the random number generator to be
controlled by external sources.
It is kept for ABI compatibility but is no longer functional, and should
not be used in new programs.
.Pp
.Fn RAND_write_file
writes a number of random bytes (currently 1024) to file
.Fa filename .
.Sh RETURN VALUES
.Fn RAND_load_file
returns
.Fa max_bytes ,
or a bogus positive value if
.Fa max_bytes
is -1.
.Pp
.Fn RAND_write_file
returns the number of bytes written, or a number less than or equal
to 1 if an error occurs.
.Pp
.Fn RAND_file_name
returns a pointer to
.Fa buf
on success or
.Dv NULL
on error.
.Sh HISTORY
.Fn RAND_load_file ,
.Fn RAND_write_file ,
and
.Fn RAND_file_name
first appeared in SSLeay 0.5.1 and have been available since
.Ox 2.4 .