How to enable terminal beeping?

Question

xterm conviniently beeps on a failed unit test (pytest):

Beeping

(start-process "" nil "/usr/bin/xterm" "-e" "python3" "-B" "-m" "pytest_watch" "--clear" "--" "-s" "--last-failed")

Now I need this beep in term or ansi-term. How can can I do this?

Not yet beeping:

(switch-to-buffer (make-term "test-term" "/bin/bash" nil "-c" "python3 -B -m pytest_watch --clear -- -s --last-failed"))
(switch-to-buffer (term-ansi-make-term "test-ansi" "/bin/bash" nil "-c" "python3 -B -m pytest_watch --clear -- -s --last-failed"))

Answer 1

pytest tells the terminal to beep by printing a BEL character, ascii 0x07. Emacs term looks for the same character and calls ding to ring the bell.

The way ding works is by looking at the variable ring-bell-function. If it is non–nil, it calls this function. However, the default value for this variable is ignore. This is a function that doesn’t do much, so generally Emacs is silent. If the variable is nil, then it falls back to an OS–specific hook which may or may not do anything. On Linux, with X Windows, this is done by calling XkbBell (or XBell, in the unlikley case that you built Emacs without Xkb). Very likely that will be handled by your desktop environment, which should allow you to customize the sound that plays.

Or you could set it to a function of your own that plays a sound by some other means, such as by running an appropriate sound–playing program on a sound file of your choosing.