extern main declaration from bsplib returns error

Question

Im setting up the bsplib (https://github.com/Zefiros-Software/BSPLib) on a windows system (in VS Code) using WSL. When compiling I get the error message:

test.cpp:4:5: error: conflicting declaration of C function ‘int main()’
    4 | int main()
      |     ^~~~
In file included from /mnt/d/study/software/bsp/include/bsp/bspExt.h:30,
                 from /mnt/d/study/software/bsp/include/bsp/bsp.h:34,
                 from test.cpp:2:
/mnt/d/study/software/bsp/include/bsp/bspClass.h:59:12: note: previous declaration ‘int main(int, char**)’
   59 | extern int main(int argc, char **argv);

The program is used is just a bare example for BSP:

#include <iostream>
#include "bsp/bsp.h"

int main()
{
    bsp_begin(bsp_nprocs());
    int s = bsp_pid();
    int p = bsp_nprocs();
    printf("Hello World from processor %d / %d", s, p);
    bsp_end();

    return 0;
}

Compiled with:

g++ -I/mnt/d/study/software/bsp/include -g -lpthread -o main test.cpp

To my (quite limited) knowledge, the 'extern' in the header file should prevent the compiler from labelling the main as 'duplicate' of some sort. Im mostly interested in some of BSPs functionalities as part of a class of mine, that sadly does not include any support on the installation. What I've done so far:

• Copied the include files from the repo
• Added the include path to the compilation (-I Flag) and the -lpthread as instructed by the class script
• Added the include path to the configuration (c_cpp_properties.json) [tested both with and without this, no difference]

Due to the many possible sources of that error (program, compiler, wsl, library, configuration, vs code, my stupidity) I cant determine where I am mistaken, nor am I able to find online resources to that combination.