does catch block share the scope of the try block?

Surprisingly, I can't find an answer to that by googling and searching SO (there are lots of similar questions on SO but related to other languages).

I suspect that the answer is no. If so, there is an obvious inconvenience, e.g.

try
{
  std::string fname = constructFileName(); // can throw MyException
  ofstream f;
  f.exceptions(ofstream::failbit | ofstream::badbit);
  f.open(fname.c_str());
  // ...
}
catch (ofstream::failure &e)
{
  cout << "opening file " << fname << " failed\n"; // fname is not in the scope
}
catch (MyException &e)
{
  cout << "constructing file name failed\n";
}

If my assumption is correct, how do you deal with this? By moving the std::string fname; out of try, I guess?

I understand that a scope is defined by a {} block, but this seems as a reasonable case for, hmm, exception. Is the reason for that that objects can be not fully constructed if an exception is thrown?

Does catch block share the scope of the try block?

No.

How do you deal with this? By moving the std::string fname; out of try, I guess?

Yes.

I understand that a scope is defined by a {} block, but this seems as a reasonable case for, hmm, exception. Is the reason for that that objects can be not fully constructed if an exception is thrown?

The last thing C++ needs is more complex rules and exceptions to rules. :-)