Re: Deadlock calling NCARG from Apache Tomcat

Hi folks,

We've been working behind the scenes on this one, and it's a
head-thumper.

As a work-around, I had Kevin add the following call before
the very end of his script:

status_exit(0)

This causes NCL to exist with an integer error code (which can be
useful if you are calling NCL from a shell script). It also,
apparently, causes NCL to exit from things differently than
just letting the script end.

Preliminary testing indicates that this was working for Kevin,
although we're both still curious why. We hope to get some information
from a Dave Brown on this, who is out of the office until tomorrow.

I probably won't post any more on this, so email me separately
if you are having a similar issue and want to know more.

--Mary

On Mon, 13 Oct 2008, Dave Allured wrote:

> Kevin,
>
> Since no one else has responded about Java and Tomcat, you probably need to
> resort to more basic debugging methods. What version of NCAR Graphics are
> you running? Did you build NCARG from source, or use pre-compiled binaries?
> What platform and OS and version is NCARG running on, when your C program is
> invoked? (uname -a)
>
> Is the program set up to output to X11 or to a file format such as Postscript
> or PDF? What statement is executed when the program locks? Are there any
> error messages? Is it possible that error messages to stdout or stderr were
> suppressed within the Java/Tomcat environment?
>
> Dave Allured
> CU/CIRES Climate Diagnostics Center (CDC)
> http://cires.colorado.edu/science/centers/cdc/
> NOAA/ESRL/PSD, Climate Analysis Branch (CAB)
> http://www.cdc.noaa.gov/
>
> Stewart, Kevin L. (GSFC-614.5)[INOVM] wrote on 2008-sep-19:
>> Hey folks,
>>
>> Has anyone seen a similar problem before or know where I can get some help?
>> I posted this a couple weeks back and didn’t see any replies.
>>
>> Kevin L. Stewart
>> Innovim
>> NASA GSFC, Code 614.5
>> 301-286-8385
>>
>> *From:* Stewart, Kevin L. (GSFC-614.5)[INOVM]
>> *Sent:* Friday, August 22, 2008 4:26 PM
>> *To:* 'ncarg-talk_at_ucar.edu'
>> *Subject:* Deadlock calling NCARG from Apache Tomcat
>>
>> Hi, I’m brand new to this list. I’m currently working for NASA on a small
>> exploration project involving visualizing science data on maps. Our main
>> application is in Java running in the Apache Tomcat application server but
>> we implemented the visualization portion in C that calls the NCAR Graphics
>> package. The visualization utility works find from the command line but
>> locks every time when we run it from Tomcat/Java. I have code in place to
>> read and flush the input and error buffer streams but that didn’t fix the
>> locking problem. As anyone else every had similar problems between NCARG
>> and Java or Tomcat? BTW, I’ve verified that the NCARG_ROOT and PATH
>> properties are defined correctly.
>>
>> Kevin L. Stewart
>> Innovim
>> NASA GSFC, Code 614.5
>> 301-286-8385
> _______________________________________________
> ncarg-talk mailing list
> ncarg-talk_at_ucar.edu
> http://mailman.ucar.edu/mailman/listinfo/ncarg-talk
>

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Received on Wed Oct 22 2008 - 14:15:59 MDT