#include <fontconfig.h>
FcBool FcCharSetAddChar(FcCharSet *fcs, FcChar32 ucs4);
FcBool FcCharSetAddChar
FcCharSetAddChar adds a single unicode char to the set, returning FcFalse on failure, either as a result of a constant set or from running out of memory.
Fontconfig version 2.8.0