wxIconLocation is a tiny class describing the location of an (external, i.e. not embedded into the application resources) icon. For most platforms it simply contains the file name but under some others (notably Windows) the same file may contain multiple icons and so this class also stores the index of the icon inside the file.
In any case, its details should be of no interest to the application code and most of them are not even documented here (on purpose) as it is only meant to be used as an opaque class: the application may get the object of this class from somewhere and the only reasonable thing to do with it later is to create a wxIcon from it.
bool IsOk() const
Returns true if the object is valid, i.e. was properly initialized, and false otherwise.