Hi all, I had a few minutes, so I decided to start playing a bit in C again. I am taking the program I wrote previously, and trying to break it up into smaller files. For example, I'm trying to get all the #defines that I do to alias to hardware pins and place them in an external header file. I want to do this so I can #include it at the top of all the other files in my project, so the constant names are universal across the project. So, I created a .h file, and cut and pasted the 4 #define lines I had in my main C file over. However, they don't seem to get an context highlighting. And, when I try to build, it exits on an error that wouldn't be there if the defines had worked. This is all with MPLABX by the way. So here's the thing. The three other #includes in my main file work fine. I have put my new header in the same folder and used double quotes to include it. I have another file that I included locally previously, and it's working fine. My header file appears in the project tree under header files. I can't see anything bad in the properties. Still, it seem like the compiler isn't actually processing that file. Anyone have any thoughts? I'm really not sure what to try next. Thanks! Josh --=20 A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .