As I'm spending some time back in the land of low-level C, I'm trying to fully get my head around best-practices for header files and code organization, so I thought I'd toss out some questions.

This is what you call a prototype. Normally, you’ll create a header file with the prototype. You can include that header in both A.c and B.c. The problem is when you change the function in A.c: ...

In C programming, a source code file that contains common definitions and data structures that all programmers may use as required. Also called "include files," because the #include statement is ...