1 files changed, 7 insertions, 0 deletions

diff --git a/lisp/comint.el b/lisp/comint.el
index b83484809eb..cdf94394d4e 100644
--- a/lisp/comint.el
+++ b/lisp/comint.el
@@ -556,6 +556,13 @@ buffer.  The hook `comint-exec-hook' is run after each exec."
 (defun comint-exec-1 (name buffer command switches)
   (let ((process-environment
          (nconc
+          ;; If using termcap, we specify `emacs' as the terminal type
+          ;; because that lets us specify a width.
+          ;; If using terminfo, we specify `unknown' because that is
+          ;; a defined terminal type.  `emacs' is not a defined terminal type
+          ;; and there is no way for us to define it here.
+          ;; Some programs that use terminfo get very confused
+          ;; if TERM is not a valid terminal type.
           (if (and (boundp 'system-uses-terminfo) system-uses-terminfo)
               (list "EMACS=t" "TERM=unknown"
                     (format "COLUMNS=%d" (frame-width)))