astMapDefined$<$X$>$astMapDefinedX - Check if a KeyMap contains a defined value for a key

Description:
This function checks to see if a KeyMapKeyMap contains a defined value for a given key. If the key is present in the KeyMap but has an undefined value it returns zero (unlike astMapHasKeyastMapHasKey which would return non-zero).
Synopsis:
int astMapDefined( AstKeyMap $*$this, const char $*$key );
Parameters:
this
Pointer to the KeyMap.
key
The character string identifying the value to be retrieved. Trailing spaces are ignored. The supplied string is converted to upper case before use if the KeyCaseKeyCase attribute is currently set to zero.
Returned Value:
astMapDefined()
A non-zero value is returned if the requested key name is present in the KeyMap and has a defined value.