100   void *cookie;  member
109        void *cookie,  in funreader()  argument
114   funcookie *c = (funcookie *) cookie;  in funreader()
116   if ((result = c->readfn (c->cookie, buf, n)) < 0 && errno)  in funreader()
123        void *cookie,  in funwriter()  argument
128   funcookie *c = (funcookie *) cookie;  in funwriter()
130   if ((result = c->writefn (c->cookie, buf, n)) < 0 && errno)  in funwriter()
137        void *cookie,  in funseeker()  argument
141   funcookie *c = (funcookie *) cookie;  in funseeker()
145   if ((result = c->seekfn (c->cookie, (fpos_t) off, whence)) < 0 && errno)  in funseeker()
150   if ((result = c->seekfn (c->cookie, (_fpos64_t) off, whence)) < 0 && errno)  in funseeker()
164        void *cookie,  in funseeker64()  argument
169   funcookie *c = (funcookie *) cookie;  in funseeker64()
171   if ((result = c->seekfn (c->cookie, off, whence)) < 0 && errno)  in funseeker64()
179        void *cookie)  in funcloser()  argument
182   funcookie *c = (funcookie *) cookie;  in funcloser()
186       if ((result = c->closefn (c->cookie)) < 0 && errno)  in funcloser()
195        const void *cookie,  in funopen()  argument
224   c->cookie = (void *) cookie; /* cast away const */  in funopen()