- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- HISTORY

# NAME

RAND_load_file, RAND_write_file, RAND_file_name - PRNG seed file

# SYNOPSIS

     #include <openssl/rand.h>

     const char *RAND_file_name(char *buf, size_t num);

     int RAND_load_file(const char *filename, long max_bytes);

     int RAND_write_file(const char *filename);

# DESCRIPTION

`RAND_file_name()` generates a default path for the random seed file. buf points to a buffer of size num in which to store the filename. The seed file is $RANDFILE if that environment variable is set, $HOME/.rnd otherwise. If $HOME is not set either, or num is too small for the path name, an error occurs.

`RAND_load_file()` reads a number of bytes from file filename and adds them to the PRNG. If max_bytes is non-negative, up to to max_bytes are read; starting with OpenSSL 0.9.5, if max_bytes is -1, the complete file is read.

`RAND_write_file()` writes a number of random bytes (currently 1024) to file filename which can be used to initialize the PRNG by calling `RAND_load_file()` in a later session.

# RETURN VALUES

`RAND_load_file()` returns the number of bytes read.

`RAND_write_file()` returns the number of bytes written, and -1 if the bytes written were generated without appropriate seed.

`RAND_file_name()` returns a pointer to buf on success, and NULL on error.

# SEE ALSO

rand, RAND_add, RAND_cleanup

# HISTORY

RAND_load_file(), `RAND_write_file()` and `RAND_file_name()` are available in all versions of SSLeay and OpenSSL.