@deftypefun {int} {gnutls_pbkdf2} (gnutls_mac_algorithm_t @var{mac}, const gnutls_datum_t * @var{key}, const gnutls_datum_t * @var{salt}, unsigned @var{iter_count}, void * @var{output}, size_t @var{length})
@var{mac}: the mac algorithm used internally

@var{key}: the initial keying material

@var{salt}: the salt

@var{iter_count}: the iteration count

@var{output}: the output value

@var{length}: the desired length of the output key

This function will derive a variable length keying material from
a password according to PKCS @code{5}  PBKDF2.

@strong{Returns:} Zero or a negative error code on error.

@strong{Since:} 3.6.13
@end deftypefun