conversion, and CODING-SYSTEM does not specify one, CODING-SYSTEM is
merged with the already-specified end-of-line conversion.
However, if the optional prefix argument FORCE is non-nil,
-then CODING-SYSTEM is used exactly as specified."
+then CODING-SYSTEM is used exactly as specified.
+
+This marks the buffer modified so that the succeeding \\[save-buffer]
+surely saves the buffer with CODING-SYSTEM. From a program, if you
+don't want to mark the buffer modified, just set the variable
+`buffer-file-coding-system' directly."
(interactive "zCoding system for visited file (default, nil): \nP")
(check-coding-system coding-system)
(if (null force)