Question

first, here is some code:

class A
{
public:
    A()
    {
        //...
        readTheFile(mySpecialPath);
        //...
    }

    A(boost::filesystem::path path)
    {
        //...
        readTheFile(path);
        //...
    }

protected:  
    void readTheFile(boost::filesystem::path path)
    {
        //First, check whether path exists e.g. by
        //using boost::filesystem::exists(path).
        //But how to propagate an error to the main function?
    }

    //...
};

int main(int argc, char **argv)
{
    A myClass;

    //Some more code which should not be run when A::readTheFile fails
}

What is a good solution to let the main function know that A::readTheFile could not open the file? I want to terminate the execution when opening the file fails.

Many thanks in advance!

Answer 1

Have readTheFile() throw an exception:

protected:  
    void readTheFile(boost::filesystem::path path)
    {
        //First, check whether path exists e.g. by
        //using boost::filesystem::exists(path).
        //But how to propagate an error to the main function?
        if (/*some-failure-occurred*/)
        {
            throw std::runtime_error("Failed to read file: " + path);
        }
    }

...

int main()
{
    try
    {
        A myObj;

        //Some more code which should not be run when A::readTheFile fails
    }
    catch (const std::runtime_error& e)
    {
        std::cerr << e.what() << "\n";
    }

    return 0;
}