Re: Open compilation window only on errors?

[Jens Schmidt]

Matthew Calhoun <calhounm@mac.com> writes:

> When I compile using M-x compile, Emacs opens a new window for
> the compilation buffer when it's finished. This is great when
> there are warnings or errors, but when there aren't I would like
> to prevent Emacs from opening the new window, and instead maybe
> just put a message in the minibuffer indicating that compilation
> was successful. Is there a variable I can set for this, or does
> anyone have elisp code that does something similar?

The following does not exactly do what you want to do since the
window on M-x compile gets opened anyway.  But you may do a C-x 1
to get rid of it and it will pop up again at end of compilation
if and only if compilation was unsuccessful.

I like the solution since you may both
- catch errors quickly that show up immediately and
- forget about long-running compilations regardless whether they
  finish up successfully or not.

(defun check-compilation-result (buffer msg)
  "Signal end of compilation.
Pops up a buffer with compilation results if necessary."
  (ding)
  (if (or (< (length msg) 8)
          (not (equal (substring msg 0 8) "finished")))
      (display-buffer buffer))
  (message (concat "Compilation " (substring msg 0 -1))))

(setq compilation-finish-function 'check-compilation-result)

Jens