[compile error] "Cannot add pcl::ColorGradientModality<pcl::PointXYZRGB> as member"

[ghost]

Issue Summary
I'm trying to create a wrapper class for pcl::LINEMOD which requires me to make pcl::ColorGradientModality and pcl::SurfaceNormalModality my member variables. I include the following headers and my .h file:

#include <pcl/recognition/color_gradient_modality.h>
#include <pcl/recognition/surface_normal_modality.h>

but the build fails with the following errors:

CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `Eigen::internal::binary_evaluator<Eigen::CwiseBinaryOp<Eigen::internal::scalar_quotient_op<float, float>, Eigen::Block<Eigen::Matrix<float, 3, 3, 0, 3, 3>, 1, 3, false> const, Eigen::CwiseNullaryOp<Eigen::internal::scalar_constant_op<float>, Eigen::Matrix<float, 1, 3, 1, 1, 3> const> const>, Eigen::internal::IndexBased, Eigen::internal::IndexBased, float, float>::binary_evaluator(Eigen::CwiseBinaryOp<Eigen::internal::scalar_quotient_op<float, float>, Eigen::Block<Eigen::Matrix<float, 3, 3, 0, 3, 3>, 1, 3, false> const, Eigen::CwiseNullaryOp<Eigen::internal::scalar_constant_op<float>, Eigen::Matrix<float, 1, 3, 1, 1, 3> const> const> const&)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:243: multiple definition of `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneRowDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:243: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneColDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:263: multiple definition of `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneColDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:263: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneRowNonDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:283: multiple definition of `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneRowNonDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:283: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneColNonDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:317: multiple definition of `pcl::filters::Convolution<pcl::PointXYZRGB, pcl::PointXYZRGB>::convolveOneColNonDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:317: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneRowDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:351: multiple definition of `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneRowDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:351: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneColDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:368: multiple definition of `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneColDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:368: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneRowNonDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:385: multiple definition of `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneRowNonDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:385: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneColNonDense(int, int)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:391: multiple definition of `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::convolveOneColNonDense(int, int)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:391: first defined here
CMakeFiles/ubt_detector.dir/src/ubt_detector.cpp.o: In function `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::makeInfinite(pcl::RGB&)':
/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:397: multiple definition of `pcl::filters::Convolution<pcl::RGB, pcl::RGB>::makeInfinite(pcl::RGB&)'
CMakeFiles/ubt_detector.dir/src/main.cpp.o:/usr/local/include/pcl-1.10/pcl/filters/impl/convolution.hpp:397: first defined here
collect2: error: ld returned 1 exit status

To Reproduce
Create simple class with pcl::ColorGradientModality as a member.

Screenshots/Code snippets/Build information

My implementation is along the following lines

MyClass.h

...
#include<pcl/recognition/color_gradient_modality.h>
...

class MyClass
{
public:
    // Member methods
protected:
   ...
   pcl::ColorGradientModality<pcl::PointXYZRGB> color_grad_mod_;
   ...
}

MyClass.cpp

...
MyClass::SomeMethod()
{
    color_grad_mod_.setInputCloud(input_cloud);
    color_grad_mod_.processInputData();
}
...

Your Environment (please complete the following information):

• OS: Ubuntu 18.04
• Compiler: clang6.0.0
• PCL Version: HEAD
• PCL Type: Installed/Compiled from source

If PCL was compiled from source or failure in compiling PCL itself:

• GPU, Kinfu, CUDA enabled? No
• List and Version of dependencies used: Boost 1.65.1, Eigen3

Possible Solution

Based on this thread the solutions seems to be to separate convolution.h member methods into a separate .cpp file instead of an

#include <pcl/recognition/impl/convolution.hpp>

at the end of the file. Similarly for color_grad_modality.h as well.

[kunaltyagi]

PCL Type: Installed/Compiled from source

Did you try using PCL_NO_PRECOMPILE?

[ghost]

@kunaltyagi

The #include <pcl/filters/impl/convolution.hpp> was not wrapped in #define guard. Even if I add the guard, the flag PCL_NO_PRECOMPILE is already set in pcl_config.h.in

[kunaltyagi]

The #include <pcl/filters/impl/convolution.hpp> was not wrapped in #define guard

That's not needed. The issue is with the full specialization. A work-around can be inline before the offending functions. If that works, please report back 😄

Even if I add the guard, the flag PCL_NO_PRECOMPILE

This is unrelated to the error (based on my diagnosis), but you can't set it... You need to compile PCL with this flag.

[ghost]

@kunaltyagi I'm new to CMake, can you explain how I can compile PCL with this flag?

[kunaltyagi]

It's not needed in this case (but it's as simple as <cmake-command> -DPCL_NO_PRECOMPILE) as the error is caused by something else.

Please try to modify PCL source code at the offending lines (adding inline along with the return type), (then installing PCL again or using sudoedit) and then compiling your code again.

[ghost]

@kunaltyagi
The inline work-around worked!! Thanks so much! Just for the record:

I made makeInfinite inline in convolution.h

The function template for

convolveRolDense
convolveRowNonDense
convolveColDense
convolveColNonDense

are inline'd but they have SPECIALIZATION in convolution.hpp that are not. So I inline'd those and my class now builds.