Re: Providing diagnostic information upon successful completion

From:
"Andrei Polushin" <polushin@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
7 Nov 2006 18:53:23 -0500
Message-ID:
<1162935639.765756.38480@e3g2000cwe.googlegroups.com>
Nicola Musatti wrote:

Hallo,
I'm looking for advice on how to provide diagnostic information related
to a function call that executed successfully.
[...]
I see a few alternatives:

1) Throw a "warning" exception, which may contain the function's
   return value when one is expected;

2) Return a special object which combines the return value with
   optional diag info,
[...]

the decision to use such a strategic approach is best left
to the users of my library.


Consider the iostreams way:

     void f()
     {
         string line;

         getline(cin, line);
         if (!cin) {
             cout << "input failed - returning";
             return;
         }

         cin.exceptions(ios::eofbit);
         try {
             getline(cin, line);
         } catch (exception &e) {
             cout << "input failed - rethrowing";
             throw;
         }
     }

User may choose a level and/or conditions at which to throw.

--
Andrei Polushin

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