Question

Is it useful to throw different exceptions for instance std::runtime_error or std::invalid_argument in huge projects? Or is it better to throw in general std::exception with a good text parameter for what()? And when does it make sence to derive some sub classes from std::exception?

Rumo

Answer 1

It always makes sense to use throw the most specific exception. As each exception should be derived from std::exception the code catching may decide at which level of granularity it wants to handle it (catch by reference! Item 13 in “More effective C++” from S. Meyers).

Using only std::exception with only some text a no-go:

• unnecessary limiting the usage possibility of the catching code
• the catching code would need to parse the text to base logic on if it had to perform different actions depending on the type of exception (whihc can be realized at lower cost with RTTI)
• I cannot think of any case where it would be benefitiable to do so. Overriding what() provides an adequate text for any exception if you need.