title: How to store an output value of 'X'
body: <p>I am programming an µC in C, and for programming I have to use a serial connection. Using this is quite easy, I just have to store the values (e.g. <code>10011000</code>) I want to send as ints, and then convert them for sending into binary and send them one after another. But now some command bytes should look like <code>XXXX1001</code>, i.e. they contain some bits which are not set. But after the transmission size is fixed to one byte per cycle, I have to fill them up somehow. Furthermore, how can I store them? Does is simply mean that these bits are neglected, and I can set them either to <code>1</code> or to <code>0</code>?</p>