什么是“提供者”字段Debian Stretch 上的通知守护进程？
是虚拟包的意思吗？
但似乎Debian Stretch 上的通知守护进程不是虚拟包，因为它有一个具体文件列表
$ aptitude show notification-daemon
Package: notification-daemon
Version: 3.20.0-1+b1
State: installed
Automatically installed: yes
Priority: optional
Section: x11
Maintainer: Debian GNOME Maintainers <[email protected]>
Architecture: i386
Uncompressed Size: 398 k
Depends: libatk1.0-0 (>= 1.12.4), libc6 (>= 2.4), libcairo2 (>= 1.10.0), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.37.3), libgtk-3-0 (>= 3.19.12), libpango-1.0-0 (>=
1.14.0), libx11-6
Provided by: cinnamon (3.2.7-4), dunst (1.1.0-2+b1), gnome-flashback (3.22.0-3), gnome-shell (3.22.3-3), lxqt-notificationd (0.11.1-1), mate-notification-daemon (1.16.1-1),
mate-notification-daemon (1.18.1-1~bpo9+1), notify-osd (0.9.35+15.04.20150126-1+b1), plasma-workspace (4:5.8.6-2.1+deb9u1), python-jarabe (0.110.0-3), xfce4-notifyd
(0.3.4-1)
Description: daemon for displaying passive pop-up notifications
notification-daemon displays passive pop-up notifications, as per the Desktop Notifications Specification.
The Desktop Notifications Specification provides a standard way of doing passive pop-up notifications on the Linux desktop. These are designed to notify the user of something
without interrupting their work with a dialog box that they must close. Passive popups can automatically disappear after a short period of time.
Homepage: https://git.gnome.org/browse/notification-daemon/
Tags: implemented-in::c, interface::daemon, interface::graphical, interface::x11, role::program, uitoolkit::gtk, use::monitor, x11::applet, x11::application
答案1
即使 B 不是虚拟的，包 A 也可以提供包 B。例如，当 A 提供与 B 相同的功能，但其他软件包依赖于 B 时，就会执行此操作。在这种情况下cinnamon，notify-osd可以安装 、 等来代替以notification-daemon满足依赖关系。