PropertyHandle :: IsUserHandle - Is property handle user-defined
The function returns, whether a property handle is user-defined (i.e. constructed by the application) or not (i.e. constructed by the system). You may turn a system handle into a user handle by calling the property handle constructor, i.e. a property handle is considered being a user handle as soon as there is at least one application property handle referring to the property handle (see also "Pointer Constructor").
Note, that GetPropertyHandle(), which returns a property handle pointer, does not change a system handle into a user handle.
In many cases, context functions should be called for user handles, only, to avoid unnecessary function calls for internal processes.
PropertyHandle *ph = GetPropertyHandle(...);
if ( !ph->IsUserHandle() )
PropertyHandle my_ph(ph);
if ( !ph->IsUserHandle() )
printf("now 'ph' is always a user handle");
The function returns YES when the question was answered positively. Otherwise it returns NO.