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howto:panel_plugin_debug [2009/01/14 07:12] – redone this page, also with gdb 88.172.125.130howto:panel_plugin_debug [2012/07/04 10:44] – [Temporarily capturing messages to stdout and stderr] belnac
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 ====== Panel Plugin Debugging ====== ====== Panel Plugin Debugging ======
-Debugging external panel plugins is possible by wrapping the executable against a shell script that runs a debug tool.+Debugging **external** panel plugins is possible by wrapping the executable against a shell script that runs a debug tool.
  
-The exec command is available inside the desktop entry file that is shipped with every panel plugin.  They are installed inside the directory $prefix/share/xfce4/panel-plugins.  If the desktop entry file contains a key X-XFCE-Module instead of X-XFCE-Exec than it means it is an internal panel plugin.+The exec command is available inside the desktop entry file that is shipped with every panel plugin.  They are installed inside the directory "''$prefix/share/xfce4/panel-plugins''".  If the desktop entry file contains a key **X-XFCE-Module** instead of **X-XFCE-Exec** than it means it is an internal panel plugin.  Internal panel plugins can be debugged by running the tools directly on ''xfce4-panel''.
  
 So, this lets you quite some possibilities to wrap an external panel plugin.  You can create a new desktop entry file just for the purpose of running it with a debug tool, you can change the desktop entry file directly to point it to the shell script, or you can rename the panel plugin binary and write a shell script as the original file. So, this lets you quite some possibilities to wrap an external panel plugin.  You can create a new desktop entry file just for the purpose of running it with a debug tool, you can change the desktop entry file directly to point it to the shell script, or you can rename the panel plugin binary and write a shell script as the original file.
  
-In the examples below we will use the first method that consists into creating a new desktop entry file.  We will also use as example a plugin called clipman that is installed inside the prefix /usr/local.+In the examples below we will use the first method that consists into creating a new desktop entry file.  We will use as example a plugin called "''clipman''" that is installed inside the prefix "''/usr/local''".
  
 ===== Debug with Valgrind (full example) ===== ===== Debug with Valgrind (full example) =====
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   #!/bin/sh   #!/bin/sh
   valgrind --log-file=$HOME/clipman-valgrind.log \   valgrind --log-file=$HOME/clipman-valgrind.log \
-  /usr/local/libexec/xfce4/panel-plugins/clipman $@+  /usr/local/libexec/xfce4/panel-plugins/clipman "$@"
  
   * Now you can add the plugin "Clipman (valgrind)" to the panel as usual   * Now you can add the plugin "Clipman (valgrind)" to the panel as usual
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 {{wiki:information.png}} It'll be really slow as wrapped in valgrind, but you'll be able to hunt memory leaks. {{wiki:information.png}} It'll be really slow as wrapped in valgrind, but you'll be able to hunt memory leaks.
  
-==== More useful call to Valgrind ====+=== More useful call to Valgrind ===
  
   G_SLICE=always-malloc G_DEBUG=gc-friendly valgrind --tool=memcheck --leak-check=full \   G_SLICE=always-malloc G_DEBUG=gc-friendly valgrind --tool=memcheck --leak-check=full \
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   #!/bin/sh   #!/bin/sh
-  gdb -ex r -ex bt -ex q --args /usr/local/libexec/xfce4/panel-plugins/clipman $@ \+  gdb -ex r -ex bt -ex continue -ex q --args /usr/local/libexec/xfce4/panel-plugins/clipman $@ \
   > $HOME/clipman-gdb.log 2>&1   > $HOME/clipman-gdb.log 2>&1
 +
 +=== Using GDB on running instances ===
 +
 +If you want an interactive debug session with GDB, you can simply find the process id of the plugin by running
 +
 +  $ gdb /usr/local/libexec/xfce4/panel-plugins/clipman $(pidof clipman)
 +  ...
 +  (gdb) continue
 +
 +which will find the PID of clipman, and debug it using the debug symbols in /usr/local/libexec/xfce4/panel-plugins/clipman. For this to work, clipman must already be running. You can also attach GDB to a process from the GDB prompt by using the attach command:
 +
 +  (gdb) attach $PID
 +
 +Again, the plugin must already be loaded for this to work.
 +
 +===== Temporarily capturing messages to stdout and stderr =====
 +
 +  * Add the plugin to the panel
 +  * Exit the panel:
 +
 +  $ xfce4-panel -q
 +
 +  * Start panel capturing stdout and stderr to file. Note that this will capture all messages from the panel, including all plugins, to 'file':
 +
 +  $ xfce4-panel > file 2>&1 & disown
 +
 +  * When done capturing, exit the panel and start it again:
 +
 +  $ xfce4-panel -q
 +  $ xfce4-panel & disown
  
 ====== Some tips ====== ====== Some tips ======
   * By creating your own desktop entry file, it will never get overwritten by any installation, and the file doesn't cause any problem.   * By creating your own desktop entry file, it will never get overwritten by any installation, and the file doesn't cause any problem.
-  * You can point the Exec= key to your development directory, for instance /home/john/clipman/panel-plugin/xfce4-clipman-plugin-gdb, and write the shell script xfce4-clipman-plugin-gdb that points to the binary inside your development directory aswell.  This avoids you to install the binary every time, all you will need is to restart the panel (''xfce4-panel -r'') :-P+  * You can point the Exec= key to your development directory, for instance /home/john/clipman/panel-plugin/xfce4-clipman-plugin-gdb, and write the shell script xfce4-clipman-plugin-gdb that points to the binary inside your development directory aswell.  This avoids you to install the binary every time, all you will need is to restart the panel (''xfce4-panel -r'') after you compile your plugin :-P