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Informix Error -55352: Unable to open display ''.

Cause and resolution

Unable to open display ''.

If the DISPLAY environment variable is undefined (for instance, after executing the rlogin or su command), define it.

If the X server access control facility is activated for this DISPLAY, you might need to run the xhost command to allow connection to the X server. You have to run the xhost command from the local computer (as the DISPLAY environment variable specifies).

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-55352 fires when the oncockpit GUI client can't open its X11 display — per the official guidance, two causes are named.

  1. The DISPLAY environment variable left undefined, per the official guidance — commonly after an rlogin or su that didn't preserve it.
  2. The X server's access control facility blocking the connection, per the official guidance, if xhost hasn't granted access to the connecting host.
Solutions / Resolution
  1. Define the DISPLAY environment variable, per the official guidance, if it's unset.
  2. Run xhost <hostname> from the local computer (the one named by DISPLAY), per the official guidance, if the X server's access control is active.
Examples
Checking and granting X display access
$ echo $DISPLAY
$ xhost <hostname>

Per the official guidance, xhost must be run from the local computer that DISPLAY specifies, not from the remote host trying to connect.

Diagnostic Checks
  1. Check whether DISPLAY is set in the environment oncockpit runs in.
  2. Check whether the X server's access control facility is active, and run xhost from the correct (local) computer if so.
Related Errors / Related Topics
  • -55276 — "connect() to host... using service... failed." Another oncockpit/onprobe connectivity error, at the network layer rather than the X11 display layer.

oncockpit couldn't open its X11 display — check that DISPLAY is set, and that xhost has granted access from the correct local computer if X access control is active.