There are two main ways of IPC control in durden. The first is through the three named pipes created in durden/ipc/control,output,status at statup. The use of status is described in statusbar and will not be covered here.
control is a default-off, unix domain socket that can be used to perform external control of the entire desktop. There is a tool in the arcan source distribution, arcan_cfgfs that can be used with FUSE to mount the file system so that you can interact with it using the normal command-line tools.
Otherwise, you can write your own tools to communicate via the trivial text protocol (commands: ls, read, exec, write, monitor) or use socat like:
socat - unix-client:$HOME/.arcan/appl-out/durden/ipc/control
All the commands end with either a single line OK and a linefeed, or an error message starting with Exxx.
Read simply lists the attributes and, depending on the path, additional metadata about a path.
name: myname label: Name Field hint: 0..1 initial: 0.3
ls will list the contents of a menu directory, terminated by a single OK and linefeed oror an EINVAL if the path doesn’t exist.
exec will invoke the currently specified action path.
write works like exec but is used for value paths, that is paths which require a value to be provided in order to work properly.
The command ‘monitor’ is special, as it will change the state of the connection to only accept monitor commands. These are used to listen to one or many of the event subsystems that make out the core of durden.
Will become very noisy, whileas:
Will only show window manager events. To get a list of currently available groups simply call monitor without any arguments and the list will be returned in the following EINVAL error message.
The second monitor command disable monitoring and returns the connection back to a normal state.
output is a FIFO used to convey custom messages, like when a user-defined statusbar button is clicked. There is also a hidden menu path (=bind only) that allows you to pass a custom message to the output channel. This path can be found at global/system/output_msg.
There is also a second, more experimental, IPC mechanism that disguises itself as a normal connected client and it is more directed towards experienced developers as you will have to hook into both durden and develop using one of the arcan-shmif API bindings, e.g. TUI (see the arcan wiki for more information) . For a simple example on how this is used to implement a clipboard manager, see clipboard.
This channel can be used for more powerful things as well, like full or partial display sharing or streaming, input injection.