How to find out whether a keyCode corresponds to an actual character or a function key?

How to find out whether a keyCode corresponds to an actual character or a
function key?

References

Reference NO 1

http://stackoverflow.com/questions/15200074/how-to-find-out-whether-a-keycode-corresponds-to-an-actual-character-or-a-functi

Reference NO 2

http://download.java.net/jdk8/docs/api/java/awt/event/KeyEvent.html

Reference NO 3

http://www.webtoolkit.eu/wt/doc/reference/html/classWt_1_1WKeyEvent.html

Reference NO 4

http://docs.wxwidgets.org/trunk/classwx_key_event.html

Reference NO 5

http://msdn.microsoft.com/en-us/library/windows/desktop/ms646267(v=vs.85).aspx

Reference NO 6

https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent

Reference NO 7

http://javascript.info/tutorial/keyboard-events

Reference NO 8

http://developer.android.com/reference/android/view/KeyCharacterMap.html