Function tomcrypt_sys::hkdf

pub unsafe extern "C" fn hkdf(
    hash_idx: c_int, 
    salt: *const c_uchar, 
    saltlen: c_ulong, 
    info: *const c_uchar, 
    infolen: c_ulong, 
    in_: *const c_uchar, 
    inlen: c_ulong, 
    out: *mut c_uchar, 
    outlen: c_ulong
) -> c_int