Re: Is this documented behaviour?

[Tyler Jameson Little]

On Wednesday, 24 July 2013 at 15:14:16 UTC, John Colvin wrote:
On Tuesday, 23 July 2013 at 16:34:54 UTC, John Colvin wrote:
void foo(ref int a)
{
        a = 5;
}
void main()
{
        int a = 0;
        int* aptr = &a;
        
        foo(*aptr);
        assert(a == 5);
        
        a = 0;
        
        int b = *aptr;
        foo(b);
        assert(b == 5);
        assert(a == 0);
}

The fact that adding an explicit temporary changes the 
semantics seems weird to me.

Thanks for the explanations people, I have now fixed a rather 
worrying mistake in my programming knowledge: WHAT IT ACTUALLY 
MEANS TO DEREFERENCE A POINTER!

Seriously, I've written programs in assembly and I still had it 
wrong. It's a wonder I ever wrote any correct code in my life.

To put the final nail in the coffin, this also works in C++:

        #include "stdio.h"

        void change(int & x) {
                x = 4;
        }

        int main(int argc, char** argv) {
                int a = 0;
                int* aptr = &a;
                change(*aptr);
                printf("%d\n", a);
        }

TBH, I was also a bit surprised because I assumed *aptr as an 
rvalue created a temporary, but as you mentioned, that's not how 
it works in assembly, so it's wrong to think it would work 
differently in C/C++/D.

Thanks for the post!