This return value is the value which a parent process can get. You got an answer on how to get this value in a batch script, but any other process can get it. This return value is called
exit status. You can read about it here:
http://en.wikipedia.org/wiki/Main_function[
^],
http://en.wikipedia.org/wiki/Exit_status[
^].
The returned value does not have special predefined meaning and is fully defined by the application, but zero is usually used to conduct the "complete without any problems" idea. The way of getting this value depends on the platform, but multiplatform programming systems/language may have some common API for spawning a child process, and, in such cases, the API usually provides a way to read exit code.
With time, the use of such a weakly defined entity as exit code somewhat declined. Many application, especially those with GUI majorly ignore the value, always returning 0. In console-only applications, using it is more usual.
—SA