al_load_ttf_font_f man page
al_load_ttf_font_f — Allegro 5 API
#include <allegro5/allegro_ttf.h> ALLEGRO_FONT *al_load_ttf_font_f(ALLEGRO_FILE *file, char const *filename, int size, int flags)
Like al_load_ttf_font(3), but the font is read from the file handle. The filename is only used to find possible additional files next to a font file.
Note: The file handle is owned by the returned ALLEGRO_FONT object and must not be freed by the caller, as FreeType expects to be able to read from it at a later time.