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.
