8 <<fopencookie>>---open a stream with custom callbacks
42 <[functions.read]> should return -1 on failure, or else the number of
46 <[functions.write]> should return -1 on failure, or else the number of
50 <[functions.seek]> should return -1 on failure, and 0 on success, with
57 <[functions.close]> should return -1 on failure, or 0 on success.  It
79 This function is a newlib extension, copying the prototype from Linux.
109   if ((result = c->readfn (c->cookie, buf, n)) < 0 && errno)  in fcreader()
122   if (c->fp->_flags & __SAPP && c->fp->_seek)  in fcwriter()
125       c->fp->_seek64 (cookie, 0, SEEK_END);  in fcwriter()
127       c->fp->_seek (cookie, 0, SEEK_END);  in fcwriter()
131   if ((result = c->writefn (c->cookie, buf, n)) < 0 && errno)  in fcwriter()
150   if (c->seekfn (c->cookie, &offset, whence) < 0 && errno)  in fcseeker()
156       offset = -1;  in fcseeker()
172   if (c->seekfn (c->cookie, &offset, whence) < 0 && errno)  in fcseeker64()
184   if (c->closefn)  in fccloser()
187       if ((result = c->closefn (c->cookie)) < 0 && errno)  in fccloser()
218       fp->_flags = 0;		/* release */  in fopencookie()
220       __lock_close_recursive (fp->_lock);  in fopencookie()
227   fp->_file = -1;  in fopencookie()
228   fp->_flags = flags;  in fopencookie()
229   c->cookie = cookie;  in fopencookie()
230   c->fp = fp;  in fopencookie()
231   fp->_cookie = c;  in fopencookie()
232   c->readfn = functions.read;  in fopencookie()
233   fp->_read = fcreader;  in fopencookie()
234   c->writefn = functions.write;  in fopencookie()
235   fp->_write = fcwriter;  in fopencookie()
236   c->seekfn = functions.seek;  in fopencookie()
237   fp->_seek = functions.seek ? fcseeker : NULL;  in fopencookie()
239   fp->_seek64 = functions.seek ? fcseeker64 : NULL;  in fopencookie()
240   fp->_flags |= __SL64;  in fopencookie()
242   c->closefn = functions.close;  in fopencookie()
243   fp->_close = fccloser;  in fopencookie()