On 2013-11-20 08:22, Jouko Koski wrote:
Ok. What if the "user" is writing a library code which calls other
system utilities? If the validation fails, is the answer now assert?
I don't have a definite answer. However, I tend to follow the practice
that all public API should do validation and throw on failures. I use
assert for catching my own mistakes in more or less internal stuff.
I neither have a definite answer. It depends on what that particular
function is doing.
Usually I don't find separate validation API functions very practical.
One can forget or ignore to do validation, just like one can fail to
check errno after a call. Of course, validation is necessary and
exceptions can assert (sic!) this. It might be more of a personal
preference, but often I catch exceptions only for error reporting
purposes. Exception is an indication of an unexpected condition in the
program. The solution is to fix the program to be prepared for the
condition, not trying to fix the condition afterwards as the exception
has already fired. Not all APIs support this approach.
I all depends on what API's and what the program is doing. Trying to
read a file which you don't have permission to read, or doesn't exist
would probably throw an exception. But that is not an error by the
programmer. It could be perfectly fine to catch that exception and ask
the user of the program to try a different file.
--
/Jacob Carlborg
