import numpy as np
from xgboost import XGBClassifier

model = XGBClassifier(use_label_encoder=False)
model.fit(np.array([[1,2],[3,4]]), np.array([0,1]))
model.save_model("model.bin")

############

#include <iostream>
#include "xgboost/c_api.h"

#define safe_xgboost(call)                                                \
  {                                                                       \
    int err_code = (call);                                                \
    if (err_code != 0) {                                                  \
      std::string error = XGBGetLastError();                              \
      std::cerr << "Error during " << #call << ":" << error << std::endl; \
      exit(1);                                                            \
    }                                                                     \
  }

int main() {
  void* booster_handle_ = nullptr;
  safe_xgboost(XGBoosterCreate(nullptr, 0, &booster_handle_));
  safe_xgboost(XGBoosterLoadModel(booster_handle_, "model.bin"));
  safe_xgboost(XGBoosterSetParam(booster_handle_, "nthread", "1"));
  if (booster_handle_ != nullptr) {
    safe_xgboost(XGBoosterFree(booster_handle_));
  }
  return 0;
}