Adds a single value to the list of values associated with the property named `object_. _I_f _`_a_p_p_e_n_d is FcTrue, the value is added at the end of any existing list, otherwise it is inserted at the begining. `value' is saved (with FcValueSave) when inserted into the pattern so that the library retains no reference to any application-supplied data structure.
Fontconfig version 2.6.0