How to Pinpoint Unhandled Exceptions: A Deep Dive into Custom Exceptions and Macros

Unveiling the Source of Unhandled Exceptions

When exceptions arise during program execution, tracing their origin can be crucial for troubleshooting. In the absence of explicit code line information embedded in the exception message, unhandled and external exceptions can leave developers in the dark.

A Deeper Dive into Custom Exceptions and Macros

To address this challenge, a robust solution involves creating a custom exception class and leveraging macros.

The my_exception class extends the std::runtime_error class and incorporates an additional msg member to store the exception message. The constructor of this class constructs the message by concatenating the source file, line number, and the original exception argument.

Next, the throw_line macro simplifies the process of throwing an exception with line information. It takes an argument representing the exception message and automatically adds the file and line number details to the my_exception object.

Putting it into Action

Consider the following code snippet:

void f() {
    throw_line("Oh no!");
}

int main() {
    try {
        f();
    }
    catch (const std::runtime_error &ex) {
        std::cout << ex.what() << std::endl;
    }
}

When an exception is thrown within the f function, the throw_line macro provides both the exception message ("Oh no!") and the line number where it occurred. This information is accessible through the my_exception object's what() method.

By utilizing this approach, developers gain a valuable tool for precisely identifying the source of exceptions, even when they originate from unhandled or external sources.

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