Understanding spdlog

[junior stream]

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@bronze salmon

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[unkempt lake]

what does a project mean in this context?

[bronze salmon]

It is a full c++ project that I created with visual studio. Each project are composed by multiple classes.
What I want to say is the following. There is an App that invokes methods from the Project 1, 2 and 3. And these projects uses methods from a Common project.

We can also consider each project as an individual component. And the App invokes each component.
My goal is that each component contains logging. In this case, should I create a unique log instance for each component?
should the log variable for each component be shared between the different classes inside each component?

[unkempt lake]

Well it depends I would propably give them each their own instance

[bronze salmon]

I also agree with you, but there are questions that I couldn't answer.

1. If I define a logging instance on each components, should I make the log variable as shared_ptr? This question is because App will invoke the methods of each components, and I am wonder if it will compile because it will not import the logging variable.

I ask you this because I had project with "error LNK2019: unresolved external symbol" on the logging variable. I think the reason is that all projects are installed as lib, and the App is installed as a dll.

So, I don't know if this problem is my fault, or are we talking about c++ issue between dll and lib.

[unkempt lake]

shared_ptr is basically always a mistake

[bronze salmon]

And how to understand shared_ptr errors? I have an error like this, and I can't understand what I am doing wrong.

This is nothing related to logging, but it is the same error.

main.obj : error LNK2019: unresolved external symbol "public: __cdecl OctreeSegmentation::OctreeSegmentation(class std::shared_ptr<class ImageContainer>)" (??0OctreeSegmentation@@QEAA@V?$shared_ptr@VImageContainer@@@std@@@Z) referenced in function main [C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\main.vcxproj]
octreesegmentation_lib.lib(octreesegmentation.obj) : error LNK2019: unresolved external symbol "public: __cdecl PlaneDetectionPostprocessor::PlaneDetectionPostprocessor(void)" (??0PlaneDetectionPostprocessor@@QEAA@XZ) referenced in function "public: void __cdecl OctreeSegmentation::plane_postprocess(class std::vector<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::allocator<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?plane_postprocess@OctreeSegmentation@@QEAAXAEAV?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@@std@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@3@1@Z) [C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\main.vcxproj]
C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\Debug\main.exe : fatal error LNK1120: 2 unresolved externals [C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\main.vcxproj]

what's going on here?

[unkempt lake]

most likely files are not being compiled correctly

that said im not sure from just this

[bronze salmon]

In a file segmentation.h (belongs to project A), I have the code

    ImageContainer(const std::string& ply_path,
                   const std::string& rgb_path,
                   const std::string& depth_path);
using ImageContainerPtr = std::shared_ptr<ImageContainer>;

In the file octreesegmentation.cpp (belongs to project B), I have the code:

OctreeSegmentation::OctreeSegmentation(ImageContainerPtr image) {    image_container = image;}

void
OctreeSegmentation::plane_postprocess(std::vector<std::string>& plane_tokens,
                                      std::string rgb_output_filename, std::string polygon_output_filename)
{
    PlaneDetectionPostprocessor plane_visualizer;
    std::cout << "Storing PNG with patches at " << rgb_output_filename << std::endl;
    std::cout << "Storing polygons info at " << polygon_output_filename << std::endl;
    plane_visualizer.visualize_plane_polygon(in_cloud, plane_tokens, rgb_output_filename, polygon_output_filename);
    return;
}

These projects compile sucessfully.

In the App, I have this snippet.

ImageContainer container = ImageContainer(input_filename, rgb_image_path, depth_image_path);
    ImageContainerPtr image_container = std::make_shared<ImageContainer>(container);
    OctreeSegmentation octreeSegmentation(image_container);
octreeSegmentation.plane_postprocess(plane_tokens, outputFileName, polygonFileName);

It seems that the problem is related to the shared_ptr<class ImageContainer>. I don't understand why?

is the example enough?

Project A and B are installed as a lib.

[unkempt lake]

im honestly not realy sure either, that said I would propably see if you can refractor this without a shared_ptr

[bronze salmon]

It seems than octreesegmentation_lib.lib(octreesegmentation.obj), which is Project A in this example, cannot find the reference to shared_ptr<ImageContainer>. Is this a problem from CMakeLists.txt, or should I have declared using ImageContainerPtr = std::shared_ptr<ImageContainer>; in the Project A?

in other words, I should have declared using ImageContainerPtr = std::shared_ptr<ImageContainer>; in Project A and B.

[unkempt lake]

hmmmm. if project B depends on project A it should be fine

[bronze salmon]

What I mean is that ImageContainer and the shared_ptr (ImageContainerPtr) is defined in Project B. Project A has a method that contains the argument ImageContainerPtr).

and the App creates a ImageContainer, that transforms it as a shared_ptr, and then invokes a method on project B and passses as an argument ImageContainerPtr variable:

    ImageContainer container = ImageContainer(input_filename, rgb_image_path, depth_image_path);
    ImageContainerPtr image_container = std::make_shared<ImageContainer>(container);
    OctreeSegmentation octreeSegmentation(image_container);

[unkempt lake]

I mean if the projects don't know about each other that could explain it

[bronze salmon]

what does this mean? Every project that uses the same shared_ptr, it should be declared the same shared_ptr on each project?

[unkempt lake]

well I meant as if projects depends on information in other projects but don't correctly link to each other

[bronze salmon]

I have removed the ImageContainerPtr variable. Now I have the following.

In project A

class ImageContainer {

public:
    ImageContainer();
    ImageContainer(const std::string& ply_path,
                   const std::string& rgb_path,
                   const std::string& depth_path);
...
}

In project B

class OctreeSegmentation {
private:
    ImageContainer image_container;
public:
    inline OctreeSegmentation(ImageContainer container);
...}

OctreeSegmentation::OctreeSegmentation(ImageContainer container)
        : image_container(container) {}

In the App

ImageContainer image_container = ImageContainer(input_filename, rgb_image_path, depth_image_path);
    OctreeSegmentation octreeSegmentation(image_container);

Unfortunately with this code, I have the error

main.obj : error LNK2019: unresolved external symbol "public: __cdecl OctreeSegmentation::OctreeSegmentation(class ImageContainer)" (??0OctreeSegmentation@@QEAA@VImageContainer@@@Z) referenced in function main [C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\main.vcxproj]
C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\Debug\main.exe : fatal error LNK1120: 1 unresolved externals [C:\Users\JumpStart\repo-git\segmentationcpp\OctreeSegmentation\apps\cmake-build-debug-visual-studio\main.vcxproj]

it is the same problem. In all CMakeLists.txt files I point to the project A.

but it seems that is not finding the reference to ImageContainer. Is this a problem of implementing the code, or a problem in the compilation?

the problem appears in the compilation of the App.

[bronze salmon]

Found the error.

The error was in the definition of OctreeSegmentation. "inline" keyword shouldn't be used.

[junior stream]

@bronze salmon

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[bronze salmon]

!solved