(Fformat): Check format control characters.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/editfns.c b/src/editfns.c
index f1f11cf2781..1f855e8480e 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -2551,7 +2551,12 @@ Use %% to put a single % into the output.")
                be a double.  */
             if (*format == 'e' || *format == 'f' || *format == 'g')
               args[n] = Ffloat (args[n]);
+            else
 #endif
+              if (*format != 'd' && *format != 'o' && *format != 'x'
+                  && *format != 'X' && *format != 'c')
+                error ("Invalid format operation %%%c", *format);
+
             thissize = 30;      
             if (*format == 'c'
                 && (! SINGLE_BYTE_CHAR_P (XINT (args[n]))