On 12/04/14 23:38, Henrique de Moraes Holschuh wrote:
> On Thu, 10 Apr 2014, Shachar Shemesh wrote:
>> I never did understand what people expect. gcc uses the undefined
> Warn the hell out of any line of code with per-spec undefined behaviour, if
> not by default, at least under -Wall.
I have no argument with that, in those places it is possible.
I will point out that it is not always is possible, and is quite often
not easy. For example, the famous "undefined after NULL dereference"
would probably cause a warning every time a function uses a pointer it
was given without first validating its non-NULLness.
> THAT would be a good start. Too bad not even gcc knows every time it hits
> undefined behaviour...
My understanding of things is that undefined behaviors are fairly
common, and almost always benign. Look at the following code:
int add( int a, int b )
{
return a+b;
}
Do you really want to get a "Warning: signed integer overflow yields
undefined behavior" on this function?
Shachar
