K 10
svn:author
V 3
0mp
K 8
svn:date
V 27
2019-08-25T17:55:31.747481Z
K 7
svn:log
V 433
mixer(8): Report an error if the passed value is an empty string

This patch fixes a bug that made the mixer command enter
an infinite loop when instructed to set the value of a device
to an empty string (e.g., `mixer vol ""`).

Additionally, some tests for mixer(8) are being added.

PR:		240039
Reviewed by:	hselasky, mav
Approved by:	src (hselasky, mav)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D21409

END