Re: KNF and the C preprocessor

[<Paul_Koning%Dell.com@localhost>]

On Dec 10, 2012, at 12:50 PM, David Holland wrote:

> On Mon, Dec 10, 2012 at 09:36:35AM -0600, David Young wrote:
> ...
> (Also, as a side issue, at least one of your examples is invalid.
> 
>> 1 Lazy evaluation: unlike a function call's arguments, a macro's
>>  arguments are not evaluated before the macro is "called."  E.g., in
>>  the code below, the second and following arguments of M(a, b, c, d, e)
>>  are not evaluated unless p(a) is true:
>> 
>>      #define M(__x, ...)                     \
>>      do {                                    \
>>              if (p(__x))                     \
>>                      f(__x, __VA_ARGS__);    \
>>      } while (false)
>> 
>>      M(a, b, c, d, e);
> 
> The C standard makes no such guarantee.)

Really?  if (false) foo (bar()); might evaluate bar() ?  Where does it say that?

        paul