[Boost-users] code snippet to add line number to lexical_cast exceptions

From: bert hubert (bert.hubert_at_[hidden])
Date: 2007-01-24 07:35:58

Hi people,

I find that I rely on lexical_cast<> a lot, it is a great thing. However,
when it throws an exception, and I catch it, I lose information on which of
the many lexical_casts had a problem. This is not a lexical_cast specific
problem of course, it would be great to have a more general way to add line
numbers to exceptions!

This led me to code up this small gcc specific hack, but I wonder if there
is a better way:

#define wrapped_atox(x, y) ({ \
      x tmp;  \
      try { tmp=boost::lexical_cast<x>(y); }	\
      catch(exception &e) { \
        throw std::runtime_error(std::string("On line " + \
        boost::lexical_cast<std::string>(__LINE__)+" of " +\
        std::string(__PRETTY_FUNCTION__)+" in " +std::string(__FILE__) +\
        ", while converting '"+string(y)+"': ") + e.what()); \
      }                           \
      tmp; \
      })

Which can be used as:

        cout << wrapped_atox(int, argv[1]) << endl;

The code above works, but is gcc specific, and well, it doesn't look right. 

Perhaps someone has a better idea? Otherwise, people may benefit from the
snippet above, feel free to copy it!

        Bert

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