Added the ability to redirect logging to a callable.

[larshg]

I'm in deep water here, but it seems to work :)

Please come with suggestions, before spent too much time in the wrong way.

Could close #5589

[larshg]

@mvieth do you have any idea to why there is linker errors with pcl::octree:OctreeKey::maxDepth ?

[mvieth]

@mvieth do you have any idea to why there is linker errors with pcl::octree:OctreeKey::maxDepth ?

Must have something to do with the usage of maxDepth here: https://github.com/PointCloudLibrary/pcl/blob/master/octree/include/pcl/octree/impl/octree_base.hpp#L98
maxDepth is a static const member, so maybe something related to ODR-use? I have to look at your changes in detail first before I can make a more specific guess.

[larshg]

Ahh, its in that print statement it fails... hmm, still odd though.

[larshg]

Maybe pcl::console::LogRecorder should be a member of the Logger, to avoid creating a stringstream for each stream command - would that make sense?

[roncapat]

Nice for me, even if I not like too much the following:

pcl::console::Logger::getInstance().setCallback(...)

because of the getInstance() call... is there a way to remove this indirection level?

Moreover, I think that the previous callback needs to be returned from the setCallaback() call to be able to restore it.

[larshg]

Nice for me, even if I not like too much the following:

pcl::console::Logger::getInstance().setCallback(...)

because of the getInstance() call... is there a way to remove this indirection level?

Moreover, I think that the previous callback needs to be returned from the setCallaback() call to be able to restore it.

Somehow the callback needs to be saved - and having just a static global variable to a std::function, didn't seem right either. At least it was the best solution I found, also browsing other logging frameworks.

[roncapat]

template <typename Functor>
void pcl::console::Logger::setCallback(Functor&& callback){
      getInstance().setCallback(std::move(callback));
}

DISCLAIMER: draft, untested code.
@larshg wouldn't this work? Would the template be a problem there?

[larshg]

You want a free function like:

    template <typename Functor>
    void
    setCallback(Functor&& callback)
    {
      Logger::getInstance().setCallback(std::move(callback));
    }

so you can call:
pcl::console::setCallback(...);

Yes, thats possible.

[roncapat]

Moreover, why generic template "functor" instead of std::function?

[larshg]

Else I couldn't get it to work with lambdas - but maybe I did it wrong 😄

[larshg]

To restore normal logging again, you can just set the callback to a nullptr.

[aurelienrb]

I had a quick look and it looks promising to me, thanks for your work

[mvieth]

I assume we are targeting PCL 1.16.0, due to likely ABI changes?

Is there a way to easily reset to the default behaviour, after calling setCallback? Edit: I just read your other comment: set callback to a nullptr. Please document this in the code somewhere.

[Copilot]

Pull Request Overview

This PR adds the ability to redirect PCL logging to a callable function, which addresses the need for programmatic access to logging output rather than just console printing. This change allows users to capture and handle log messages in custom ways.

• Introduces a callback-based logging system with LogRecord structure
• Refactors existing print functions to use templates and std::string instead of C-style variadic arguments
• Replaces deprecated static member variables with static getter functions

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
common/include/pcl/console/print.h	Adds Logger class with callback support and converts print functions to templates
common/src/print.cpp	Implements Logger singleton and callback-based printing logic
test/common/test_console.cpp	New test file for validating logging functionality and callback behavior
test/common/CMakeLists.txt	Adds test registration for console testing
sample_consensus/include/pcl/sample_consensus/sac_model.h	Replaces deprecated static member with getter function
octree/include/pcl/octree/octree_key.h	Replaces deprecated static member with getter function
octree/include/pcl/octree/impl/octree_pointcloud.hpp	Updates to use new getter function
octree/include/pcl/octree/impl/octree_base.hpp	Updates to use new getter function and adds missing includes
octree/include/pcl/octree/impl/octree2buf_base.hpp	Updates to use new getter function
octree/src/octree_inst.cpp	Adds missing include for octree_key.h
octree/include/pcl/octree/octree_impl.h	Removes redundant include
tools/train_linemod_template.cpp	Updates print calls to use std::string instead of .c_str()
examples/segmentation/example_lccp_segmentation.cpp	Simplifies logging by removing stringstream usage
examples/segmentation/example_cpc_segmentation.cpp	Simplifies logging by removing stringstream usage