Re: Is this code safe? (std::exception constructor with local char*)

From:
kalman <mendola@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Sat, 9 Aug 2008 23:44:36 CST
Message-ID:
<acb5b8e1-2b5c-4d59-9da0-a4b6748c91cf@w7g2000hsa.googlegroups.com>
On Aug 4, 5:21 am, Mathias Gaunard <loufo...@gmail.com> wrote:

On 3 ao?t, 22:19, francis_r <francis.ramme...@gmail.com> wrote:

Is the following code safe?

{
   std::string exceptionString = "Test";
   throw std::exception(exceptionString.c_str());

}


Obviously not.
How can a local variable survive stack unwinding?


Obviously can work indeed, if only the std::exception would have a
constructor taking
a const *. Anyway it doesn't then doesn't work. The statement:

"How can a local variable survive stack unwinding" doesn't make sense
indeed throw
a local variable is legal code, remember that in a constructor like:

try {

}
catch( std::exception &e ) {
   ...
}

even if the exception is catched per reference the runtime makes a
copy o the
data thrown so there is no problem at all to throw a local variable.

Regards
Gaetano Mendola

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