Re: How to determine where an exception is thrown?

From:

"Ben Voigt [C++ MVP]" <bvoigt@newsgroup.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 3 Jun 2009 14:57:35 -0500

Message-ID:

<eBZgLWI5JHA.1092@TK2MSFTNGP06.phx.gbl>

Ulrich Eckhardt wrote:

Fred wrote:

[...] I'm wondering how to determine where an exception is thrown.
It's difficult to judge the throw point when lots of statement may
throw same exception. For example:

try
{
    vector<int> vec_foo;
    vec_foo.puch_back( 1 );
    vec_foo.puch_back( 2 );
    std::cout << vec_foo.at(3); // pos1
    ......
    std::cout << vec_foo.at(4); // pos2
}

catch( std::exception& e )
{
    ... // log error
}

When check the log, it's possible to find something like "Exception
in file: main.cpp, Line:73, Function:main, message : invalid
vector<T> subscript", but how to determine whether the exception is
thrown in pos1 or pos2?

You can't. It could even be the pos0 or pos-1, i.e. the push_back's,

You can't using only portable standard C++.

But with Visual C++, you can, by using the /EHa compiler option and using
__try/__except, and the GetExceptionInformation macro + dbghelp api (or just
log the instruction pointer and use your debugger to find which line of
code, then you don't have to ship your symbols). Or write a minidump which
will contain the exception information, you can load that into a debugger
and see the exact line, call stack, and also current values of variables.