Function r_core::r_hash_do_hmac_sha256

pub unsafe extern "C" fn r_hash_do_hmac_sha256(
    ctx: *mut r_hash_t, 
    input: *const c_uchar, 
    len: c_int, 
    key: *const c_uchar, 
    klen: c_int
) -> *mut c_uchar