(calc-convert-temperature): Ensure that units are on the result

even when the result is zero.

2 files changed, 13 insertions, 3 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 35163804e3a..5a645e75e3c 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2007-12-31  Jay Belanger  <jay.p.belanger@gmail.com>
+
+        * calc/calc-units.el (calc-convert-temperature): Ensure that units
+        are on the result even when the result is zero.
+
 2007-12-30  Michael Albinus  <michael.albinus@gmx.de>
 
         * net/dbus.el (dbus-name-owner-changed-handler): Make the function
diff --git a/lisp/calc/calc-units.el b/lisp/calc/calc-units.el
index a7c4b20e30d..ac1c0cd0080 100644
--- a/lisp/calc/calc-units.el
+++ b/lisp/calc/calc-units.el
@@ -491,9 +491,14 @@ If EXPR is nil, return nil."
      (when (eq (car-safe unew) 'error)
        (error "Bad format in units expression: %s" (nth 2 unew)))
      (math-put-default-units unew)
-     (calc-enter-result 1 "cvtm" (math-simplify-units
-                                  (math-convert-temperature expr uold unew
-                                                            uoldname))))))
+     (let ((ntemp (calc-normalize
+                   (math-simplify-units
+                    (math-convert-temperature expr uold unew
+                                              uoldname)))))
+       (if (Math-zerop ntemp)
+           (setq ntemp (list '* ntemp unew)))
+       (let ((calc-simplify-mode 'none))
+         (calc-enter-result 1 "cvtm" ntemp))))))
 
 (defun calc-remove-units ()
   (interactive)