On Thursday, 14 July 2016 at 16:47:20 UTC, Ola Fosheim Grøstad
wrote:
On Thursday, 14 July 2016 at 16:17:19 UTC, Jesse Phillips wrote:
I still haven't found someone who can explain how C++ can
define the behavior of modifying a variable after casting away
const.
C++ is locked down in a mine-field of backward compatibility
issues and a need to interface with C verbatim (directly
including C header files where const parameters might lack the
const modifier).
D does not work with C header files and can redefine the
interfaces to fit D semantics in C bindings...
That doesn't explain how you can define the behavior:
void foo(int const* p) {
*(const_cast<int*>(p)) = 3;
}
Does 'p' get modified or is the program going to crash or
something else? Please define it for me. C++ says: You can't
modify the location pointed to by 'p' from 'p', using const_cast
on 'p' you'll either get undefined behavior or it will modify the
location 'p' points to. So it is defined to either be undefined
or modify the location 'p' refers to. The language isn't able to
tell you what will happen so how can it define the behavior?
