Converting a ulong to a byte array and constructing a ulong from it

[welkam]

On Thursday, 24 October 2019 at 14:08:36 UTC, 9898287 wrote:
> Does this contain any undefined behavior? It is in C as far as 
> I knew.

immutable int number = 1;
auto bad_idea = (cast(ubyte*) &number)[0 .. number.sizeof];
bad_idea[0] = 2;
writeln(number); //1
writeln(*(cast(int*)bad_idea.ptr)); //2

Cast is a powerful tool and with it you can destroy all type 
systems guarantees. In your case you will not have any problems 
just stay away from const and immutable