Re: why Ada type casting is different from other languages? newType(value) vs. (newType)value

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 14-07-15 21:42 , G.B. wrote:

> And later, is it really good or bad if it takes years or not
> to be competent enough to understand
> 
>   ptrdiff_t x = *(ptrdiff_t*)main;
> 
> vs
> 
>   X : Integer_Address := To_Integer (Main'Address);
> 
> if they are comparable?

Aah... they are *not* "comparable", if by that you mean "equivalent".
The first (C) declaration interprets the entry address of "main" as a
pointer to a ptrdiff_t, and then dereferences that pointer to read this
putative ptrdiff_t value and store it in x. In other words, x will
contain bits from the initial instructions of "main".

The second (Ada) declaration simply converts the entry address of "Main"
to an Integer_Address. It does not read anything from the instructions
in Main.

Perhaps I misunderstood your point?

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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