Fetches the GDEF class of the requested glyph in the specified face.
The #hb_face_t to work on
The #hb_codepoint_t code point to query
The #hb_ot_layout_glyph_class_t glyph class of the given code point in the GDEF table of the face.
Fetches the GDEF class of the requested glyph in the specified face.