 0 - exit with no error
 1 - Cen't access witch right mode (read or write) configuration file.
 2 - (not used),
 3 - Variable of given path not found (path not found).
 4 - Variable path not given.
 5 - Can't remove root element (cused if someone try to unset it)
 6 - Can't find parent element
 7 - Variable unset failed.
 8 - Configuration file write failed.
 9 - Variable value not given.
10 - Inconsistent value type (caused if set exisitng variablen and give type another then saved).
11 - Variable set failed.
12 - Incorrect data format.
13 - Variable type not given (in som cases tu set variable, giving his type are necesery).
14 - Inlegal data type (caused if user give type thet not known for libconfig9).
15 - Bad name of variable (curently chcecking only if enpty stringa are given).
16 - Inavlid configuration variable path.
17 - New named configuration variable can be added only to group element.
18 - Prohibited data type (caused when use type then connot be use in given case).