title: Best way to define 2 bytes for easy use with array initialization / comparing in C?
body: <p>Again, I am fairly new to C so forgive the simplicity / stupidity of this question. Anyway, here it goes. What is the best way to #define a 2 byte macro (i.e. #define MSGID 0xABCD) in C that is easy to put inside a byte array but also compare the contents of with if statements?</p>
  
  <p>To clarify this, take the 0xABCD example again. Say I want to do an:</p>
  
  <pre><code>unsigned char test_msg[] = { 0x00, 0x01, 0x02, MSGID, 0x03, 0x04, 0x05 };
  </code></pre>
  
  <p>With how I defined it above, it won't work because it's defined as a large int and gcc truncates it to an unsigned type. When I define it as #define MSGID 0xAB,0xCD it seems to work fine, but I don't understand what the comma does there and that doesn't look very clean. Another option I found that works, but also not clean, is splitting it like #define MSGIDCLASS 0xAB then #define MSGID 0xCD.</p>
  
  <p>I would also like to compare these MSGID bytes and at the moment I'm having to constantly do an if(data[n] == MSGIDCLASS &amp;&amp; data[n+1] == MSGID) ... for every message I need to parse and respond to. I was wondering if there was an easier way of doing this, that's all. If not, I'll leave it as is. Thanks again for the help. Sorry for not using the code sample tags, didn't think they were necessary with one liners.</p>