Re: [Boost-users] Wave: how to recover after errors?

6 Dec 2005

      On 12/5/05 11:28 PM, "Max Motovilov"  wrote:

[SNIP]
...
Here's my sample snippet:
try {
wave_context::iterator_type p = ctx.begin(), last_known_good = p;
bool done = false;
while( !done ) {
try {
 done = p == ctx.end();
There's a problem with the previous line.  You can't dereference "p" if
you're at the end, but you don't prevent it.
...
std::cout << p->get_value();
 ++p;
 last_known_good = p;
} catch( boost::wave::preprocess_exception& err ) {
 if( err.get_severity() >= boost::wave::util::severity_error ) throw;
 complain( err );
 p = last_known_good;
}
}
} catch( boost::wave::cpp_exception& err ) {
complain( err );
return false;
}
[TRUNCATE]
Maybe your problems are caused by dereference violation.  Try something
like:

//========================================================================
using namespace boost::wave;

try {
    typedef wave_context::iterator_type  iterator;

    iterator        last_known_good = ctx.begin();
    iterator const  e = ctx.end();

    for ( iterator i = last_known_good ; e != i ; )
    {
        try {
            std::cout << i->get_value();
            last_known_good = ++i;
        } catch ( preprocess_exception &  err ) {
            if ( err.get_severity() >= util::severity_error )
                throw;
            complain( err );
            i = last_known_good;
        }
    }
    //...
} catch ( cpp_exception &  err ) {
    complain( err );
    return false;
}
//========================================================================

Looking at this, I still don't see how you avoid reading the problem context
element over and over....

-- 
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT hotmail DOT com