[CWB] [ cwb-Bugs-2960898 ] CWB::CQP hangs if CQP backend crashes

[SourceForge.net]

Bugs item #2960898, was opened at 2010-02-28 22:42
Message generated for change (Settings changed) made by andrewhardie
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=722303&aid=2960898&group_id=131809

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: CWB/Perl interface
>Group: TODO-3.0
Status: Open
Resolution: None
Priority: 8
Private: No
Submitted By: Stefan Evert (schtepf)
Assigned to: Stefan Evert (schtepf)
Summary: CWB::CQP hangs if CQP backend crashes

Initial Comment:
The CWB::CQP interface has been reported to hang if the CQP backend crashes (because it waits for input on the stdout/stderr pipes from CQP).

Possible solutions: (i) check the pipe handles for exceptions and/or error conditions in addition to available data; (ii) install a handler for SIGCHLD that exits gracefully or at least terminates the Perl script with a meaningful error message (since this should never have happened in the first place.

Both approaches need only a little time and perusal of manpages, but will have to be tested thoroughly.  There is a comment in the CWB::CQP source code that catching SIGCHLD messes up the entire pipe closing mechanism in Perl (also for pipes that are _not_ related to the Perl process).  So solution (i) might be the way to go.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=722303&aid=2960898&group_id=131809