determines the size of a file
INCLUDE 'iolib.h' filesize(Size,"tmp.dat"),
integer(Size) (o) size of the file
string(FileName) (i) name of the file to be examined
The size of the file associated with filehandle returned.
A runtime error if handle is not valid.
prolog-process, client-server, object
filepos , deletefile , openwrite , tell