kicad-developers team mailing list archive

[Lorenzo Marcantonio <l.marcantonio@xxxxxxxxxxxx>]

On Tue, Jun 03, 2014 at 08:18:52AM +0200, Heiko Rosemann wrote:
> Probably the way to do this formally correct and without relying on
> implicit integer-boolean conversion would be the following:
> if( (ip = s1.Intersect( s_next )) != 0 )

Best of all MISRA-C recommends

if (0 != stuff())

because even in the == case, a mistyped = won't compile. Paranoid stuff,
of course (to avoid memory access errors they simply somewhat banned
pointers). However be careful in C++:

if (stuff())

triggers an implicit to-bool conversion where

if (0 != stuff())

uses an implicit to-int conversion (due to integral promotion)

And for to-bool implicit conversion there is a special rule. An you could
have defined an operator bool() but not an operator int(). Obviously it
depends on what stuff() returns exactly... Usual C++ nasty need-to-know
stuff. See http://en.cppreference.com/w/cpp/language/implicit_cast

-- 
Lorenzo Marcantonio
Logos Srl