If you find that Posadis has problems such as crashing, stopping the answering of queries, or starting a large number of threads, you can help fixing the problem by debugging it. You won’t need programming experience; just follow the crash course presented here.

To debug Posadis under Windows, you will need to have a debug build of Posadis. Normal Posadis releases are not debug builds; it’s best to ask me, for example on the forum, to make a debug build for you.

If you have a debug build, all you need to do install a so-called Just in Time Debugger, called Dr. Mingw. Nowadays, Dr. Mingw is part of the Mingw utils package, but you can get a standalone version here.

Install Dr. Mingw by running

drmingw -i

This should give a message indicating that Dr. Mingw was succesfully installed. See the Dr. Mingw website for more info. Next time Posadis crashes, the familiar Windows crash dialog will have an option to debug the program, after which Dr. Mingw is run, which will give information on the problem; e-mail that to me and you’ve helped me debugging the program.

Alternately, you can attach to a running Posadis by finding out its Process ID (PID) through the task manager, and run

drmingw -p 

where is the PID of the Posadis process.

For Unix (and Windows too, as a matter of fact), you can make your own debug build of Posadis programs using the –enable-debug configuration option; see building for more information. To make the debugging information more useful, you should also run a debugging version of Poslib.

You can make Posadis dump debug information when it crashes by enabeling the core dump functionality of your OS; how to do this may differ between Unices, but it may be something like:

ulimit -c unlimited

Next time, Posadis will leave a file with core in its name in the working directory it was started from (usually, a message like “Segmentation fault (core dumped)” will be displayed. Say the file is called core.1, you can then run gdb:

gdb core.1

From GDB, enter thread apply all bt and post the output here (see Documentation for more information on filing bugs).

Alternately, to attach to a running Posadis, you can find out its PID using something like ps ax, and then attach to it using

gdb attach 

where is the PID of the Posadis process. In GDB, enter the run command with any arguments you want to pass to Posadis. When Posadis has stopped reponding or started taking up 100% CPU, press CTRL-C and, as above, post the output of thread apply all bt.