RQT Custom Plugin: undefined symbol

edit

Hi everyone,

I am trying to have a simple RQT template to use in the future whenever I need to create a new GUI. The main idea of my minimal (not) working example (MNWE) is to have:

• TemplatePlugin class that is exported as plugin for RQT;
• TemplateWidget class that implements an RQT widget that is then included in TemplatePlugin.

This is a similar approach employed in rqt_multiplot where there's one main MultiplotPlugin that includes different widgets.

I'm able to compile my (MNWE) , but when I launch the gui I get the following error:

[ERROR] [1511538332.555287110]: Failed to load nodelet [rqt_template_plugin::TemplatePlugin_0] of type [rqt_template_plugin::TemplatePlugin]: Failed to load library /home/marco/catkin_ws/devel/lib//librqt_template_plugin.so. Make sure that you are calling the PLUGINLIB_EXPORT_CLASS macro in the library code, and that names are consistent between this macro and your XML. Error string: Could not load library (Poco exception = /home/marco/catkin_ws/devel/lib//librqt_template_plugin.so: undefined symbol: _ZN19rqt_template_plugin14TemplatePluginD1Ev)

RosPluginlibPluginProvider::load_explicit_type(rqt_template_plugin::TemplatePlugin) failed creating instance PluginManager._load_plugin() could not load plugin "rqt_template_plugin::TemplatePlugin": RosPluginlibPluginProvider.load() could not load plugin "rqt_template_plugin::TemplatePlugin"

Even though the error suggests that I don't have the macro "PLUGINLIB_EXPORT_CLASS", it is actually present in my cpp file: PLUGINLIB_EXPORT_CLASS. So I guess I am not linking the plugin at compile time correctly and then having issue at run time. I tried the solution proposed in this other thread question/215487, but adding "set(CMAKE_AUTOMOC ON)" to make CMakeLists.txt file prevents me compiling the whole package.

Update of 27/11/2017

Running the command

for f in $(find ~/catkin_ws -name "*.so"); do echo $f; objdump -TC $f | grep _ZN19rqt_template_plugin14TemplatePluginD1Ev; done

the symbol "_ZN19rqt_template_plugin14TemplatePluginD1Ev" is not found at all. Whereas if I run the command

for f in $(find ~/catkin_ws -name "*.so"); do echo $f; objdump -TC $f | grep rqt_template_plugin; done

Then I obtain:

/home/marco/catkin_ws/devel/lib/librqt_template_plugin.so
/home/marco/catkin_ws/devel/lib/librqt_template_plugin.so:     file format elf64-x86-64
0000000000000000      D  *UND*  0000000000000000              
rqt_template_plugin::TemplatePlugin::~TemplatePlugin()
0000000000000000      D  *UND*  0000000000000000              
rqt_template_plugin::TemplatePlugin::~TemplatePlugin()
0000000000000000      D  *UND*  0000000000000000              non-virtual thunk to 
rqt_template_plugin::TemplatePlugin::~TemplatePlugin()
0000000000000000      D  *UND*  0000000000000000              non-virtual thunk to 
rqt_template_plugin::TemplatePlugin::~TemplatePlugin()

* End Update *

I was wondering if anyone could give me a hint about what I should try next.

Thanks a lot,

Marco.