extern int x1f4_land_lxfile (void *lxfile, void *file, int *stored);
x1f4_land_lxfile function stores the number of bytes buffered by the
file file object at
lxfile is expected the file
library object for which
file was created.
The function returns
0 for success, non zero if the number of buffered
bytes cannot be determined or in not applicable for
file (such is the
case for not opened files).