Function line_keylet 

pub unsafe fn line_keylet(
    account1_ptr: *const u8,
    account1_len: usize,
    account2_ptr: *const u8,
    account2_len: usize,
    currency_ptr: *const u8,
    currency_len: usize,
    out_buff_ptr: *mut u8,
    out_buff_len: usize,
) -> i32