Easily create string message for exception

[bramp]

Hi,
For a long time I’ve wondered if there is a simplier way to do this, but I’ve never found it. If I have the following code:

void SomeClass::SomeMethod(const char *arg) {
   If (someTestOfTheArgFailed)
      throw std::invalid_argument (“Invalid argument ‘” + arg + “’”);
}

Now obviously the above code doesn’t work, because I can’t do “Invalid argment ‘” + arg. The alternative would be to do:

If (someTestOfTheArgFailed) {
   std::string s;
   s += " Invalid argument '";
   s += arg;
   s += "'";
   throw std::invalid_argument (s);
}

This works but has needlessly added extra lines.

It would be cool if I could use some kind of printf syntax, or use operator<<.

Is there some clever trick I can use to do this all on one line still? Perhaps a function or macro I could develop? This is just so I can make my error handling code neater. I don't want to have 4-5 lines for each error message.

Thanks
Andrew