package build fails when message_filters::Subscriber is assigned a callback for receving a new message

[theksg]

ROS 2 Jazzy, Ubuntu 24.04.1(WSL)

I am syncing 2 subscribers and running a callbck with synced messages. It is working fine.

For one of the subscribers, I want to execute a callback whenever new message is received.

TimeSyncNode() : Node("sync_node")
{
  rclcpp::QoS qos = rclcpp::QoS(10);
  temp_pub = this->create_publisher<sensor_msgs::msg::Temperature>("temp", qos);
  fluid_pub = this->create_publisher<sensor_msgs::msg::FluidPressure>("fluid", qos);

  temp_sub.subscribe(this, "temp", qos.get_rmw_qos_profile());
  fluid_sub.subscribe(this, "fluid", qos.get_rmw_qos_profile());

  // Register a callback for temp_sub
  temp_sub.registerCallback(std::bind(&TimeSyncNode::TempSubCallback, this, _1));

  timer = this->create_wall_timer(500ms, std::bind(&TimeSyncNode::TimerCallback, this));
  second_timer = this->create_wall_timer(550ms, std::bind(&TimeSyncNode::SecondTimerCallback, this));

  uint32_t queue_size = 10;
  sync = std::make_shared<message_filters::Synchronizer<message_filters::sync_policies::
    ApproximateTime<sensor_msgs::msg::Temperature, sensor_msgs::msg::FluidPressure>>>(
    message_filters::sync_policies::ApproximateTime<sensor_msgs::msg::Temperature,
    sensor_msgs::msg::FluidPressure>(queue_size), temp_sub, fluid_sub);

  sync->setAgePenalty(0.50);
  sync->registerCallback(std::bind(&TimeSyncNode::SyncCallback, this, _1, _2));

}

void TempSubCallback(const sensor_msgs::msg::Temperature::SharedPtr msg) {
  // Log the receipt of a new temperature message
  RCLCPP_INFO(this->get_logger(), "Received temperature message.");
  // Add any additional processing logic here
}

I am getting build failure, I am trying this because in doc page, it is shown that callback can be attached to the subscriber,
https://github.com/ros2/message_filters/blob/jazzy/doc/index.rst#:~:text=Python%3A%20callback(msg)-,2.2%20Example%20(C%2B%2B),-message_filters%3A%3ASubscriber%3Cexample_interfaces

but when i try to do the same, i get build failure as following:

Starting >>> msg_filter_demo
--- stderr: msg_filter_demo
/home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp: In member function ‘void TimeSyncNode::TempSubCallback(sensor_msgs::msg::Temperature_<std::allocator<void> >::SharedPtr’:
/home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:93:69: warning: unused parameter ‘msg’ [-Wunused-parameter]
   93 | void TempSubCallback(const sensor_msgs::msg::Temperature::SharedPtr msg) {
      |                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from /opt/ros/jazzy/include/message_filters/message_filters/subscriber.h:44,
                 from /home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:7:
/opt/ros/jazzy/include/message_filters/message_filters/simple_filter.h: In instantiation of ‘message_filters::Connection message_filters::SimpleFilter<M>::registerCallback(const C&) [with C = std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>; M = sensor_msgs::msg::Temperature_<std::allocator<void> >]’:
/home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:33:30:   required from here
/opt/ros/jazzy/include/message_filters/message_filters/simple_filter.h:72:67: error: no matching function for call to ‘std::function<void(const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&)>::function(const std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>&)’
   72 |     typename CallbackHelper1<M>::Ptr helper = signal_.addCallback(Callback(callback));
      |                                                                   ^~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/13/functional:59,
                 from /opt/ros/jazzy/include/rclcpp/rclcpp/utilities.hpp:19,
                 from /opt/ros/jazzy/include/rclcpp/rclcpp/logging.hpp:25,
                 from /opt/ros/jazzy/include/rclcpp/rclcpp/copy_all_parameter_values.hpp:27,
                 from /opt/ros/jazzy/include/rclcpp/rclcpp/rclcpp.hpp:171,
                 from /home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:1:
/usr/include/c++/13/bits/std_function.h:435:9: note: candidate: ‘template<class _Functor, class _Constraints> std::function<_Res(_ArgTypes ...)>::function(_Functor&&) [with _Constraints = _Functor; _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}]’
  435 |         function(_Functor&& __f)
      |         ^~~~~~~~
/usr/include/c++/13/bits/std_function.h:435:9: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/13/bits/move.h:37,
                 from /usr/include/c++/13/bits/new_allocator.h:36,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/c++allocator.h:33,
                 from /usr/include/c++/13/bits/allocator.h:46,
                 from /usr/include/c++/13/memory:65,
                 from /opt/ros/jazzy/include/rclcpp/rclcpp/rclcpp.hpp:169:
/usr/include/c++/13/type_traits: In substitution of ‘template<bool _Cond, class _Tp> using std::__enable_if_t = typename std::enable_if::type [with bool _Cond = false; _Tp = void]’:
/usr/include/c++/13/bits/std_function.h:353:8:   required by substitution of ‘template<class _Res, class ... _ArgTypes> template<class _Cond, class _Tp> using std::function<_Res(_ArgTypes ...)>::_Requires = std::__enable_if_t<_Cond::value, _Tp> [with _Cond = std::function<void(const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&)>::_Callable<const std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>&, std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>, std::__invoke_result<std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>&, const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&> >; _Tp = void; _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}]’
/usr/include/c++/13/bits/std_function.h:434:9:   required from ‘message_filters::Connection message_filters::SimpleFilter<M>::registerCallback(const C&) [with C = std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>; M = sensor_msgs::msg::Temperature_<std::allocator<void> >]’
/home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:33:30:   required from here
/usr/include/c++/13/type_traits:116:11: error: no type named ‘type’ in ‘struct std::enable_if<false, void>’
  116 |     using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
      |           ^~~~~~~~~~~~~
/opt/ros/jazzy/include/message_filters/message_filters/simple_filter.h: In instantiation of ‘message_filters::Connection message_filters::SimpleFilter<M>::registerCallback(const C&) [with C = std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>; M = sensor_msgs::msg::Temperature_<std::allocator<void> >]’:
/home/sakshamg/msg_filter_ws2/src/msg_filter_demo/src/approximate_time_synchronizer.cpp:33:30:   required from here
/usr/include/c++/13/bits/std_function.h:404:7: note: candidate: ‘std::function<_Res(_ArgTypes ...)>::function(std::function<_Res(_ArgTypes ...)>&&) [with _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}]’
  404 |       function(function&& __x) noexcept
      |       ^~~~~~~~
/usr/include/c++/13/bits/std_function.h:404:27: note:   no known conversion for argument 1 from ‘const std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>’ to ‘std::function<void(const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&)>&&’
  404 |       function(function&& __x) noexcept
      |                ~~~~~~~~~~~^~~
/usr/include/c++/13/bits/std_function.h:386:7: note: candidate: ‘std::function<_Res(_ArgTypes ...)>::function(const std::function<_Res(_ArgTypes ...)>&) [with _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}]’
  386 |       function(const function& __x)
      |       ^~~~~~~~
/usr/include/c++/13/bits/std_function.h:386:32: note:   no known conversion for argument 1 from ‘const std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>’ to ‘const std::function<void(const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&)>&’
  386 |       function(const function& __x)
      |                ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/13/bits/std_function.h:375:7: note: candidate: ‘std::function<_Res(_ArgTypes ...)>::function(std::nullptr_t) [with _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}; std::nullptr_t = std::nullptr_t]’
  375 |       function(nullptr_t) noexcept
      |       ^~~~~~~~
/usr/include/c++/13/bits/std_function.h:375:16: note:   no known conversion for argument 1 from ‘const std::_Bind<void (TimeSyncNode::*(TimeSyncNode*, std::_Placeholder<1>))(std::shared_ptr<sensor_msgs::msg::Temperature_<std::allocator<void> > >)>’ to ‘std::nullptr_t’
  375 |       function(nullptr_t) noexcept
      |                ^~~~~~~~~
/usr/include/c++/13/bits/std_function.h:368:7: note: candidate: ‘std::function<_Res(_ArgTypes ...)>::function() [with _Res = void; _ArgTypes = {const std::shared_ptr<const sensor_msgs::msg::Temperature_<std::allocator<void> > >&}]’
  368 |       function() noexcept
      |       ^~~~~~~~
/usr/include/c++/13/bits/std_function.h:368:7: note:   candidate expects 0 arguments, 1 provided
gmake[2]: *** [CMakeFiles/approximate_time_sync.dir/build.make:76: CMakeFiles/approximate_time_sync.dir/src/approximate_time_synchronizer.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:137: CMakeFiles/approximate_time_sync.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2
---
Failed   <<< msg_filter_demo [8.78s, exited with code 2]

Summary: 0 packages finished [9.26s]
  1 package failed: msg_filter_demo
  1 package had stderr output: msg_filter_demo

from the code at :https://github.com/ros2/message_filters/blob/jazzy/include/message_filters/subscriber.h, i feel that we cannot assign it a callback, let me know if I am doing something wrong, or we cannot assing callback for latest messages via messsage_filters::Subscriber

[khaledgabr77]

Hi,
Try to change from:
sync->registerCallback(std::bind(&TimeSyncNode::SyncCallback, this, _1, _2));

To:
sync->registerCallback(&TimeSyncNode::SyncCallback, this);