1 files changed, 4 insertions, 1 deletions

diff --git a/src/coding.c b/src/coding.c
index 9cd493ab062..6a3868b016d 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -7819,7 +7819,10 @@ updated by the functions `make-coding-system' and
 On detecting a coding system, Emacs tries code detection algorithms
 associated with each coding-category one by one in this order.  When
 one algorithm agrees with a byte sequence of source text, the coding
-system bound to the corresponding coding-category is selected.  */);
+system bound to the corresponding coding-category is selected.
+
+When you modify this variable, `update-coding-systems-internal' must
+be called.  */);
   {
     int i;