Re: [Valgrind-developers] const arguments to matchIRExpr()

[Paul F. <pa...@fr...>]

On 23 Dec 2016, at 04:04, Ivo Raisr wrote:

> 
> 
> 2016-12-21 21:29 GMT+01:00 <pa...@fr...>:
> 
> > It also tells the compiler where aggressive optimization is possible.
> 
> 
> Unfortunately, mainly due to pointers/references and aliasing, this isn't as often as one might hope.
> 
> For instance see
> 
> http://www.gotw.ca/gotw/081.htm
> 
> An interesting reading, indeed.
> 
> Me being not a great C++ coder, would some please mind explaining the meaning of "const" here for this method:
> char operator[]( size_t ) const;

Hi Ivo

If you have a class C with method f() like this

class C
{
public:
    void f();
};

then in C++ f has an 'implicit this', which means that the actual code generated will be like

void C::f(C* this).

Since the 'this' pointer is implicit, there's no way to make it const in the formal parameter list, i.e., you can't write

void C:f(C const* this).

So in order to make the 'this' pointer const, the language allows putting const after the member declaration,, i.e.,

class C
{
public:
    void f() const;
};

A+
Paul