[boost] Re: Re: std::exception -- Re: Re: Re: Re: Re:AttemptingresolutionofThreads&ExceptionsIssue

From: Eric Woodruff (Eric.Woodruff_at_[hidden])
Date: 2002-08-16 09:37:03

The point is that thread exceptions can not be rethrown intact.

----- Original Message -----
From: Victor A. Wagner, Jr.
Newsgroups: gmane.comp.lib.boost.devel
Sent: Thursday, 2002:August:15 11:26 PM
Subject: Re: Re: std::exception -- Re: Re: Re: Re:
Re:AttemptingresolutionofThreads&ExceptionsIssue

One of use is clearly confused here....
Change your example program as shown and tell me what happens.
At Thursday 2002/08/15 16:55, you wrote:
>Since the compiler always creates its own instance of an exception when you
>throw something, the following causes the invalid_argument to be sliced:
>
>
>#include <iostream>
>#include <stdexcept>
>
>int main () {
>         try {
>                 try {
>                         throw std::invalid_argument ("argument is
invalid");
>                 }
>                 catch (std::exception& exception) {
>                         throw exception;

Change the above line to:
                 throw;

>                 }
>         }
>         catch (std::invalid_argument& exception) {
>                 std::cout << "invalid argument found" << std::endl;
>         }
>         catch (std::exception& exception) {
>                 std::cout << "generic std::exception found" << std::endl;
>         }
>
>         return 0;
>}
>
>This means that even with a valid std::exception& type caught from a
thread,
>it is impossible to have the user catch it as anything besides an
>std::exception*. However, this may make it trivial to migrate to using
>shared_ptrs of exceptions because the concrete exception types need not be
>known, thus, a wrapper can easily be written to rethrow exceptions as
>shared_ptrs.
>
>The other option is to have to have disperate catching semantics for calls
>to thread.join () and a non-threaded function. While the user can specify
>that the thread supports std::exception&, they will have to catch an
>std::exception* (the user isn't responsible for deleting it) -- this may or
>may not be acceptable.
[deleted]
Victor A. Wagner Jr.      http://rudbek.com
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