matplotlib for c++ gives this error: 'PyObject_CallObject': function does not take 3 arguments

Question

I have microsoft visual studio 2019 and installed matplotlib for it using nuget but when I want to build this code:

#include "matplotlibcpp.h"
namespace plt = matplotlibcpp;
int main() {
    plt::plot({ 1,3,2,4 });
    plt::show();
}

it gives this error: 'PyObject_CallObject': function does not take 3 arguments

this is the build output:

1>------ Build started: Project: ConsoleApplication3, Configuration: Debug Win32 ------
1>ConsoleApplication3.cpp
1>C:\Users\matthijs\source\repos\ConsoleApplication3\packages\matplotlib-cpp.1.1.0.92\include\matplotlibcpp\imshow.h(58,21): error C2660: 'PyObject_CallObject': function does not take 3 arguments
1>C:\Users\matthijs\source\repos\ConsoleApplication3\packages\matplotlib-cpp.1.1.0.92\sandbox\include\abstract.h(363,29): message : see declaration of 'PyObject_CallObject'
1>C:\Users\matthijs\source\repos\ConsoleApplication3\packages\matplotlib-cpp.1.1.0.92\include\matplotlibcpp\imshow.h(58,40): message : 'PyObject_CallObject': function declaration must be available as none of the arguments depend on a template parameter
1>Done building project "ConsoleApplication3.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

and the full error:

Severity    Code    Description Project File    Line    Suppression State   Suppression State
Error   C2660   'PyObject_CallObject': function does not take 3 arguments   ConsoleApplication3 C:\Users\matthijs\source\repos\ConsoleApplication3\packages\matplotlib-cpp.1.1.0.92\include\matplotlibcpp\imshow.h  58      

how to fix this? I used nuget to install the lasted version of matplotlib

the error happens here: PyObject* res = PyObject_CallObject(detail::_interpreter::get().s_python_function_imshow, plot_args, kwargs); I have a windows 10 laptop and I use python 3.7

Answer 1

As the error says, "PyObject_CallObject" does not take 3 args. Looking at some docs I found on a quick google , it looks like your args (plot_args, kwargs) need to be in a tuple - they need to all be within one arg to PyObject_CallObject.