Compiler didn't error on function with no return statement

[Andy Falanga (afalanga)]

Hi everyone,

I need some help in understanding why my GCC didn't consider this an issue.  I have a function that was constructing a path to a daemon program based on the location of the shared object file where this code is.  Something similar to this:

namespace {
    std::string ConstructPath()
    {
        int lastSlash(0);
        std::string pathVar;
        Dl_info dl_info;
        memset(&dl_info, 0, sizeof(dl_info));

        if((dladdr((void*)ConstructPath, &dl_info)) == 0)
        {
            throw std::runtime_error("Failed to get address ");
        }

        pathVar = dl_info.dli_fname;
        lastSlash = pathVar.find_last_of('/');
        if(std::string::npos == lastSlash)
        {
            // no slashes given ... must be that *.so
            // is in the current directory
            pathVar = "mydaemond";
        }
        else
        {
            pathVar.erase(pathVar.begin() + (lastSlash + 1), pathVar.end());
            pathVar.append("mydaemond");
        }

        // first check if we can find the daemon
        {
            // introducing sub-scope to ensure the file object is closed
            std::ifstream test(pathVar.c_str());
            if(!test.good())
            {
                throw std::runtime_error("cannot find mydaemond");
            }
        }

        // *** the below statement wasn't there originally, the
        // *** function simply exited after the forced-scope block above,
        // *** however, the function *did* have the return type
        return pathVar;
    }
}

My comments above the final return statement illustrate what my question is about.  Why wasn't this a problem?  There was no return statement and yet, the code compiled fine.  I'm using GCC 4.4.4 on CentOS 6.2.  Is this just a problem with the 4.4.4 compiler that was fixed?  I'm betting there's some subtlety in C++ here that I'm not yet aware of and I'd like to be schooled.

Thanks,
Andy