Development Coding standards

All Code

• Please use Linux line-endings (LF, no CR).
• Please try to keep diff minimal. If you really feel some re-formatting is necessary, please do it in a separate commit to ease review
• Keep lines reasonably short (80 chars for flight, 100 for GCS), break statements over multiple lines where necessary
• Use default cases in switch statements only where you really intend it, they neuter compile-time checking of missed code when new enumerations are introduced

Flight Code (C)

The flight side code has historically tried to stick as much as possible with the linux kernel style.

New Draft Guidelines

Always defer to K&R conventions when not explicitly covered here.

• Use TABS, not spaces

• Use typedefs only when strictly necessary

  • One exception is for device handles where they appear in public declarations of PiOS drivers

• case statements are indented at the same level as the parent switch

• Use spaces around parentheses for if, switch, etc., but not for functions.

• Opening braces are on the same line as if, switch, etc. else is on the same line as previous closing brace, e.g.

  if (this_thing) {
      switch (this_thing) {
      case THING_1:
          do_some_stuff();
          break;
      case THING_2:
          do_other_stuff();
          break;
      }
  } else {
      do_that_other_thing();
  }

• Braces are optional for single statement ifs, but ONLY if all branches have no braces. e.g. Okay:

  if (this_thing)
      do_stuff();
  else if (other_thing)
      do_other_stuff();
  else
      return NULL;

  NOT okay:

  if (this_thing)
      do_stuff();
  else {
      PIOS_DEBUG_Assert(false);
      return NULL;
  }

• ... more to come ...

GCS Code (C++)

Use Qt style and Qt coding conventions

• Use 4 SPACES, not tabs
• DON'T assume that returned pointers are non-null
• Use dynamic UAVO relations where you can, these will (soon) be checked at compile time against UAVO definitions
• Recommended reading: https://doc.qt.io/archives/qq/qq13-apis.html