1 files changed, 2 insertions, 1 deletions

diff --git a/src/floatfns.c b/src/floatfns.c
index 0e9003722d7..b51073b296e 100644
--- a/src/floatfns.c
+++ b/src/floatfns.c
@@ -647,7 +647,8 @@ This is the same as the exponent of a float.")
     XSET (val, Lisp_Int, exp-1);
   }
 #else
-  Well, what *do* you have?
+  /* Would someone like to write code to emulate logb?  */
+  error ("`logb' not implemented on this operating system");
 #endif
 #endif