1 files changed, 3 insertions, 2 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 16744acba88..e62dd0ec489 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -11743,8 +11743,9 @@ immediately after running `post-command-hook'.  */);
 
   DEFVAR_LISP ("input-method-function", Vinput_method_function,
                doc: /* If non-nil, the function that implements the current input method.
-It's called with one argument, a printing character that was just read.
-\(That means a character with code 040...0176.)
+It's called with one argument, which must be a single-byte
+character that was just read.  Any single-byte character is
+acceptable, except the DEL character, codepoint 127 decimal, 177 octal.
 Typically this function uses `read-event' to read additional events.
 When it does so, it should first bind `input-method-function' to nil
 so it will not be called recursively.