for P99_BLK_MARK P99_BLOCK_DOCUMENT P99_CASERANGE P99_DO P99_FORALL P99_GUARDED_BLOCK P99_HANDLE_ERRNO P99_INVARIANT P99_MARK P99_NOP P99_PARALLEL_DO P99_PARALLEL_FOR P99_PARALLEL_FORALL P99_PROTECT P99_PROTECTED_BLOCK P99_SIMPLE_BLOCKS P99_UNCASE p99_unwind P99_UNWIND p99_unwind_code P99_UNWIND_PROTECT P99_UNWIND_RETURN

P99_UNWIND_RETURN #define P99_UNWIND_RETURN Value: /* we use a special form of short circuit evaluation here, since \ setjmp is only allowed in restricted contexts */ \ switch (!!p00_unwind_bottom) \ case 1: \ /* If an unwind is possible, i.e if we are not in the outer frame \ this will stop the evaluation of the expression here, and unwind \ as side effect. Otherwise, this will continue normally and \ directly proceed with the return. */ \ if (!setjmp(p00_unwind_bottom[0]->p00_buf)) { \ /* assign before we unwind all the way down */ \ p00_unwind_bottom[0]->p00_returning = 1; \ P99_UNWIND(-p99_unwind_return); \ } else case 0: P99_ALLOW(RETURN) return Return from the enclosing function after unwinding all levels of nested P99_UNWIND_PROTECT. By this you can guarantee that all eventually existing P99_PROTECT parts of enclosing P99_UNWIND_PROTECT are properly executed. This is in some way similar to the guarantee of C++ to call destructors before returning from a function. There is one important difference, though: the return expression (if any) is evaluated after the protected parts are unwound. So if these modify parts of that return expression you might not get what you expect. So instead of P99_UNWIND_RETURN expr; You might want do something like volatile retType myret = expr; P99_UNWIND_RETURN myret; Warning Utilities that change control flow in an unexpected way may result in the loss of some modifications that are effected on variables. A modern compiler should tell you when you are in such a situation. If it is the case you'd have to declare the variable in question with the volatile qualifier. For an explanation see P99_UNWIND_PROTECT. Definition at line 691 of file p99_block.h.