-funopen(cookie, readfn, writefn, seekfn, closefn)
- const void *cookie;
- int (*readfn)(), (*writefn)();
- fpos_t (*seekfn)(void *cookie, fpos_t off, int whence);
- int (*closefn)();
+funopen(const void *cookie,
+ int (*readfn)(void *, char *, int),
+ int (*writefn)(void *, const char *, int),
+ fpos_t (*seekfn)(void *, fpos_t, int),
+ int (*closefn)(void *))