* I still say there is no basis whatever for believing that the result of ferror() is an exit code, errno code, or anything else with significance beyond zero-or-not. Feeding it to wait_result_to_exit_code as you've done here is not going to do anything but mislead people in a platform-dependent way. Probably should set exit_code to -1 if ferror reports trouble.
Agreed. Sorry, I read your comment wrong the last time or I would have already made it so.
* Why do you have wait_result_to_exit_code defaulting to return 0 if it doesn't recognize the code as either WIFEXITED or WIFSIGNALED? That seems pretty misleading; again -1 would be a better idea.
That makes sense as well. Given that WIFSIGNALED is currently defined as the negation of WIFEXITED, whatever default result we have here is basically a this-should-never-happen. That might be something we want to catch with an assert, but I'm fine with a -1 for now.
