On 19.02.2012 02:17, H. S. Teoh wrote:
The basic problem with C++ exceptions is that it allows you to throw
literally *anything*. Which is nice and generous, but not having a
common root to all exceptions cripples the system, because there is no
functionality that can be depended upon, like toString when what you
want is an error message.
No, that is a misunderstanding (completely).
However, C++ exceptions do have many problems, including:
* Until C++11, no support for propagating exceptions through
non-exception-aware code (in particular, from C callbacks).
* No support for wchar_t exception text, i.e. *nix-specific.
* A nonsensical exception class hierarchy with e.g.
std::logic_error and std::bad_exception.
* No differentiation between recoverable (soft, failure) and
unrecoverable (hard, error) exceptions, although some people have
argued that in the latter case one is screwed anyway.
* Involving std::string arguments, so that in low memory
conditions throwing an exception can itself throw.
Especially the last point is pretty silly. :-)
And then when C++11 added support for propagating error codes, it was
designed as *nix-specific (char-based messages only) and overly complex.
I haven't heard about anyone actually using that stuff.
Furthermore, not having a properly designed skeletal hierarchy to
inherit from also adds to the problem. With no existing standard
hierarchy to serve as a reference point, library writers just invent
their own systems, most of which don't interoperate properly with each
other. And thus the mess that is the C++ exception hierarchy.
I certainly hope D can do better than that.
Agreed.
Cheers,
- Alf
