I am trying to understand how to use Ensures() in code. As given in the example, if I tried using Ensures() as follows...
int main(void)
{
int result = 0;
// Some calculation
Ensures(result == 255);
return 0;
}
If the result variable is not equal to 255, the program crashes with the following output "terminate called without an active exception". My question is how to use Ensures() properly?
Are you using the Microsoft GSL implementation? Then if you check the gsl_assert.h header file you will see that if GSL_TERMINATE_ON_CONTRACT_VIOLATION is defined (which is default) then Ensures will call std::terminate which will give you the error you get.
If you want an exception to be thrown (with file and line-number information) then you need to define GSL_THROW_ON_CONTRACT_VIOLATION before including the GSL.
As for if you're using Ensures properly, then yes you are.
GSL_TERMINATE_ON_CONTRACT_VIOLATION is removed, always calling terminate().