C Tutorial, Rinker and Wall

C/C++ C Programming Tutorial

C Programming Made Easy

C for Beginners

Software State Machines

Simple Methods for Zero Crossing Detection

Power of 10 – Rules for Developing Safety Critical Code

Nutshell version:

1. Restrict all code to very simple control flow constructs — do not use goto statements, setjmp or longjmp constructs, or direct or indirect recursion.
2. Give all loops a fixed upper bound. It must be trivially possible for a checking tool to prove statically that a loop cannot exceed a preset upper bound on the number of iterations.
3. Do not use dynamic memory allocation after initialization.
4. No function should be longer than what can be printed on a single sheet of paper in a standard format with one line per statement and one line per declaration. Typically this means no more than about 60 lines of code per function.
5. The code’s assertion density should average to minimally two assertions per function.
6. Declare all data objects at the smallest possible level of scope.
7. Each calling function must check the return value of non-void functions, and each called function must check the validity of all parameters provided by the caller.
8. The use of the preprocessor must be limited to the inclusion of header files and simple macro definitions. Token pasting, variable argument lists (ellipses), and recursive macro calls are not allowed.
9. The use of pointers must be restricted. Specifically, no more than one level of dereferencing should be used.
10. All code must be compiled, from the first day of development, with all compiler warnings enabled at the most pedantic setting available. All code must compile without warnings. All code must also be checked daily with t least one, but preferable more than one, strong static source code analyzer and should pass all analyses with zero warnings.