typedef struct _TTF_Font TTF_Font;
The opaque holder of a loaded font. You should always be using a pointer of this type, as in TTF_Font*, and not just plain TTF_Font. This stores the font data in a struct that is exposed only by using the API functions to get information. You should not try to access the struct data directly, since the struct may change in different versions of the API, and thus your program would be unreliable.