What does "Set an Input handler" mean in Eclipse?

In Eclipse, when configuring an external tool (开发者_JS百科Run->External Tools->External Tools Configurations...), specifically an Ant Build, under the Main tab there is a checkbox labeled "Set an Input Handler". This is checked by default.

What does this do? When would you want to uncheck it and what would the benefits be?

I believe this is when you are using the input Ant Task, which can need an InputHandler.

When a task wants to prompt a user for input, it doesn't simply read the input from the console as this would make it impossible to embed Ant in an IDE.
Instead it asks an implementation of the org.apache.tools.ant.input.InputHandler interface to prompt the user and hand the user input back to the task.