\docparam{filename}{The filename.}
-\docparam{mode}{The mode in which to open the file using standard C strings.}
+\docparam{mode}{The mode in which to open the file using standard C strings.
+Note that you should use {\tt "b"} flag if you use binary files under Windows
+or the results might be unexpected due to automatic newline conversion done
+for the text files.}
\docparam{fp}{An existing file descriptor, such as stderr.}