(direct-print-region-function): Try to ensure that

printer-name is expanded to a file name on a local drive;
sometimes printing a file loaded from a network volume fails.
(direct-print-region-function): Add a function to
write-region-annotate-functions to append a formfeed character to
the region being printed, if the region doesn't end with a
formfeed already.  This avoids creating a second print job
containing a blank page when print spooling is enabled on Windows.

1 files changed, 20 insertions, 12 deletions

diff --git a/lisp/dos-w32.el b/lisp/dos-w32.el
index 4adeb7752b4..624519b6ff7 100644
--- a/lisp/dos-w32.el
+++ b/lisp/dos-w32.el
@@ -273,21 +273,29 @@ START and END."
   (let* ((coding coding-system-for-write)
          (coding-base
           (if (null coding) 'undecided (coding-system-base coding)))
-         (eol-type (coding-system-eol-type coding-base)))
+         (eol-type (coding-system-eol-type coding-base))
+         (write-region-annotate-functions
+          (cons
+           (lambda (start end)
+             ;; Make each print-out start on a new page, but don't waste
+             ;; paper if there was a form-feed at the end of this file.
+             (if (not (char-equal (char-after (1- end)) ?\C-l))
+                 `((,end . "\f"))))
+           write-region-annotate-functions)))
     (or (eq coding-system-for-write 'no-conversion)
         (setq coding-system-for-write
               (aref eol-type 1)))       ; force conversion to DOS EOLs
-    (write-region start end
-                  (or (and (boundp 'dos-printer) dos-printer)
-                      printer-name)
-                  t 0)
-    ;; Make each print-out start on a new page, but don't waste
-    ;; paper if there was a form-feed at the end of this file.
-    (if (not (char-equal (char-after (1- end)) ?\C-l))
-        (write-region "\f" nil
-                      (or (and (boundp 'dos-printer) dos-printer)
-                          printer-name)
-                      t 0))))
+    (let ((printer (or (and (boundp 'dos-printer)
+                            (stringp (symbol-value 'dos-printer))
+                            (symbol-value 'dos-printer))
+                       printer-name))
+          ;; It seems that we must be careful about the directory name
+          ;; that gets added by write-region when using the standard
+          ;; "PRN" or "LPTx" ports.  The call can fail if the directory
+          ;; is on a network drive.
+          (safe-dir (or (getenv "windir") (getenv "TMPDIR") "c:/")))
+      (write-region start end
+                    (expand-file-name printer safe-dir) t 0))))
 
 ;; Set this to nil if you have a port of the `lpr' program and
 ;; you want to use it for printing.  If the default setting is