(readchar): Find the previous byte's address properly

for the buffer case, as for the marker case.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/lread.c b/src/lread.c
index f07ec2dc780..0d7238ddf35 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -218,8 +218,12 @@ readchar (readcharfun)
           readchar_backlog = bytepos - orig_bytepos;
         }
 
-      return *(BUF_BEG_ADDR (inbuffer) + XMARKER (readcharfun)->bytepos
-               - readchar_backlog--);
+      /* We get the address of the byte just passed,
+         which is the last byte of the character.
+         The other bytes in this character are consecutive with it,
+         because the gap can't be in the middle of a character.  */
+      return *(BUF_BYTE_ADDRESS (inbuffer, XMARKER (readcharfun)->bytepos - 1)
+               - --readchar_backlog);
     }
   if (EQ (readcharfun, Qget_file_char))
     {