如何在 Visual Studio Code 的 C++ 项目中使用外部库

Question

I am very new to this so bear with. I have been trying to figure out the basics of starting a project in c++ in vs code but I cannot figure out how to use an external library. In order to experiment I have got a simple setup with just a HelloWorld.cpp file as well as tasks.json and c_cpp_properties.json files. I am running the file by creating a HelloWorld executable.

I have looked into using vcpkg and I have got through all the steps to get it set up (including integration) but I can't seem to get it to work. As a test I am trying to use the "opencv2" library, but if I try to use #include <opencv2/opencv2.hpp> at the top of the HelloWorld.cpp file I just get an error saying that the file could not be found.

here's what my c_cpp_properties.json file looks like:

{
"configurations": [
    {
        "name": "Mac",
        "includePath": [
            "${default}"
        ],
        "defines": [],
        "macFrameworkPath": [],
        "compilerPath": "/usr/bin/clang++",
        "cStandard": "gnu17",
        "intelliSenseMode": "${default}"
    }
],
"version": 4
}

This is my tasks.json:

{
"version": "2.0.0",
"tasks": [
    {
        "type": "cppbuild",
        "label": "C/C++: clang++ build active file",
        "command": "/usr/bin/clang++",
        "args": [
            "-std=c++17",
            "-stdlib=libc++",
            "-g",
            "${file}",
            "-o",
            "${fileDirname}/${fileBasenameNoExtension}"
        ],
        "options": {
            "cwd": "${workspaceFolder}"
        },
        "problemMatcher": [
            "$gcc"
        ],
        "group": {
            "kind": "build",
            "isDefault": true
        },
        "detail": "compiler: /usr/bin/clang++"
    }
]
} 

and finally HelloWorld.cpp:

#include <iostream>
#include <stdio.h>
#include <opencv2/opencv2.hpp>

using namespace std;

int main() {
    cout << "\n Hello World \n";
    return 0;
}

I have done a lot of experimenting with adding different includePaths etc, but no luck. I think that vcpkg claims, however, that by using user-wide integration it is not necessary to specify includePaths? I think there must be something very simple that I'm missing but I can't seem to figure out what it is. Thanks for any help!

*Just edited the question as I realised the problem was slightly different to what I thought

Answer 1

When you run the command to compile the code, you can pass the actual path to the library, to the compiler so that it can find the files needed. For example, check out the following command.

clang++ HelloWorld.cpp -I/path to the opencv include folder/include -L/path to the opencv lib folder/lib -o output

Passing the paths explicitly like this is not really necessary if you had installed OpenCV properly using cmake by following their documentation since the compiler will be able to find it.