Returns the value associated with key under group_name as an integer.
If key cannot be found then 0 is returned and throws is set to
KEY_NOT_FOUND. Likewise, if the value associated with key
cannot be interpreted as an integer then 0 is returned and throws is set to
INVALID_VALUE.
| this |
a KeyFile |
| group_name |
a group name |
| key |
a key |
|
the value associated with the key as an integer, or 0 if the key was not found or could not be parsed. |