Re: [Valgrind-users] No "Use of uninitialised value" warning

[Colin M. <col...@pi...>]

André Wöbbeking wrote:
> Hi,
>
> I'm using Valgrind 3.4.1 and I wonder why I don't get a warning for the 
> std::swap() call in the attached example. I get one in printf(). Is this 
> a bug?
>
>
> Cheers,
> André
>   
> ------------------------------------------------------------------------

André,

Valgrind only reports when an unused variable is used for flow-control 
(or, hopefuly I/O).

Swapping doesn't trigger the alert. This is because, in C, structures 
can legitimately have
uninitialised areas due to nested unions or padding.

printf() uses flow-control to decide how many characters to print.

HTH,
Colin S. Miller