Functions, nothrow and assert

[Lodovico Giaretta via Digitalmars-d-learn]

On Thursday, 8 September 2016 at 11:40:17 UTC, Russel Winder 
wrote:
> Is the fact that:
>
>     void f() nothrow {
>     	    assert(1 == 0);
>     }
>
>     int main() {
>     	    f();
>     	    return 0;
>     }
>
> compiles fine but at run time f does indeed throw an exception 
> what should happen? If it is what does nothrow actually mean?

To expand on the previous correct answers, nothrow is about not 
throwing Exceptions. Exceptions are part of the normal flow of 
the program: they are used to signal recoverable errors, much 
like error codes.

Errors, on the other hand, are unrecoverable system failures that 
should not be catched (catching them is undefined behaviour, I 
think) and will surely lead to a crash. Errors are not covered by 
nothrow.

Asserts throw Errors, not Exceptions. The reason is that asserts 
are used to test conditions that must hold, at the point that an 
optimizing compiler can analyze the expression inside the assert 
and optimize the executable based on the truthness of that 
condition. So if an assert is found false at runtime, the code 
may not be able to work at all. That's why asserts throw Errors 
and not Exceptions.