h1. Debugging

If you're encountering situations where NNTPGrab suddenly disappears and doesn't seem to be running anymore, then you're probably having a _segmentation fault_ which means that the program (or one of the components it's using) tried to do something which isn't allowed. To investigate such _segmentation fault's_ it's recommended to generate a stack trace and send it along your bugreport

h2. Windows (32bit)

For Windows 32 bits environments, the generation of a stack trace is done automatically whenever a _segmentation fault_ occurs. This stack trace is saved in a file called _nntpgrab_gui.rpt_. Depending on the Windows version you're using this file can be found at the following location:
* Windows XP: C:\Program Files\NNTPGrab\bin\nntpgrab_gui.rpt
* Windows Vista/7 with UAC enabled (default): C:\Users\your_username\AppData\Local\VirtualStore\Program Files\NNTPGrab\bin
* Windows Vista/7 with UAC disabled: C:\Program Files\NNTPGrab\bin\nntpgrab_gui.rpt

If the file _nntpgrab_gui.rpt_ cannot be found one in the folders mentioned above, you can try to collect a stack trace manually.
For this you need to download the files "gdb.exe":http://ftd4linux.nl/contrib/gdb.exe and "libexpat-1.dll":http://ftd4linux.nl/contrib/libexpat-1.dll and save them to the folder C:\Program Files\NNTPGrab\bin (or C:\Program Files (x86)\NNTPGrab\bin if you're using a 64bit version of Windows).

Now open a cmd window and execute the following set of commands:
<pre>C:\
cd "Program Files\NNTPGrab\bin"
gdb nntpgrab_gui.exe
run</pre>
NNTPGrab should get started now. Now try to reproduce the crash you were having earlier. If you succeed in doing so, the program won't disappear anymore but it will hang. Now switch back to your cmd window and execute the following commands:
<pre>thread apply all bt
thread apply all bt full
info locals</pre>
You will see several lines of output (you might get the question to press <ENTER> to continue, please do so). All this output is necessary to diagnose the crash, so please send it along with your bugreport.

If all information is collected, type the command _quit_ in the cmd window to close the debugger and NNTPGrab

h2. Windows (64bit)

If you're using the Windows 64bit version of NNTPGrab, then you need to catch _segmentation fault's_ using the debugger _gdb_. This can be found "here":http://ftd4linux.nl/contrib/gdb64.exe. Please save this file to the folder C:\Program Files\NNTPGrab\bin (or wherever you've installed NNTPGrab). Now open a cmd window and execute the following set of commands:
<pre>C:\
cd "Program Files\NNTPGrab\bin"
gdb64 nntpgrab_gui.exe
run</pre>
NNTPGrab should get started now. Now try to reproduce the crash you were having earlier. If you succeed in doing so, the program won't disappear anymore but it will hang. Now switch back to your cmd window and execute the following commands:
<pre>thread apply all bt
thread apply all bt full
info locals</pre>
You will see several lines of output (you might get the question to press <ENTER> to continue, please do so). All this output is necessary to diagnose the crash, so please send it along with your bugreport.

If all information is collected, type the command _quit_ in the cmd window to close the debugger and NNTPGrab

h2. Mac OS X

On Mac OS X it's much easier to generate a stack trace. It's done automatically when a _segmentation fault_ occurs in NNTPGrab! In this situation, a popup will be shown automatically mentioning that a crash has occured in NNTPGrab. In this popup there's an option to report this to the developers. Click this button and send all the information you get to see now along the bugreport

h2. Linux

On Linux you need gdb to catch _segmentation fault's_. On most Linux environments this package is installed by default. If not, please use the package manager of your distribution to install the _gdb_ package.

Now open a terminal and execute the following set of commands:
<pre>gdb nntpgrab_gui
run</pre>
NNTPGrab should get started now. Now try to reproduce the crash you were having earlier. If you succeed in doing so, the program won't disappear anymore but it will hang. Now switch back to your cmd window and execute the following commands:
<pre>thread apply all bt
thread apply all bt full
info locals</pre>
You will see several lines of output (you might get the question to press <ENTER> to continue, please do so). All this output is necessary to diagnose the crash, so please send it along with your bugreport.

If all information is collected, type the command _quit_ in the terminal to close the debugger and NNTPGrab