set wserv_type

Synopsis

/set wserv_type [screen|xterm|tmux]
/set -wserv_type

Default: screen. With no value, set displays the current value. Names are case-insensitive. Unsetting leaves backend selection to its environment-based fallback.

Description

Selects a preference for window create when a terminal multiplexer and an X display are both available. In particular, running under GNU Screen with an X display leaves a choice between another Screen window and a separate Xterm window. EPIC also supports the corresponding tmux case.

This is not an unconditional backend selector. The launcher checks environment variables in the following order; the first matching row applies:

Environment present	Selection
`STY` and `DISPLAY`	`xterm` selects Xterm; `screen`, `tmux`, or unset selects Screen.
`TMUX` and `DISPLAY`	`xterm` selects Xterm; `screen`, `tmux`, or unset selects tmux.
`TMUX`	tmux, regardless of this setting.
`STY`	Screen, regardless of this setting.
`DISPLAY` and `TERM`	Xterm, regardless of this setting.
None of those combinations	Creation fails because EPIC cannot choose a backend.

The checks test whether variables exist, not whether their contents are nonempty. If both STY and TMUX are present with DISPLAY, the first row wins. Without DISPLAY, tmux takes precedence over Screen. Selecting tmux while in the first row does not launch tmux; it falls back to that row's Screen backend.

Effects and errors

An unsupported value produces SET WSERV_TYPE must be either SCREEN, XTERM or TMUX and clears the setting; it does not retain the previous value. Later creation then uses the fallback shown above.

Changing the setting does not immediately create a screen or reconfigure an existing helper. A later creation still requires foreground operation, a compatible wserv_path, and the selected external program. Backend options come from screen_options, tmux_options, or xterm_options. This setting sends no IRC request.

Example

Prefer Xterm when already running in Screen or tmux with an X display available:

/set wserv_type xterm
/window create

Without the relevant display environment, the preference cannot force Xterm. Use /set -wserv_type to restore environment-based fallback selection.

History

The backend-selection setting was introduced in EPIC4-1.1.14.

Source references

source/vars.c: registration and set_wserv_type validation, including clearing unsupported values.
include/config.h: screen default.
source/screen.c: create_additional_screen implements ordered environment tests and backend-specific launches.