C and Python call each other

Python calls C functions

It is relatively simple to call C functions in Python.
Here are two examples, one is to directly call the parameters, and the other is to call the structured
C code

typedef struct {
    int i1;
    int i2;
    char str[20];
} core_data_t;

__declspec(dllexport) int add(int a, int b)
{
    return a + b;
}

__declspec(dllexport) int multi(int a, int b)
{
    return a * b;
}

__declspec(dllexport) int struct_add(core_data_t* data)
{
    printf("%s\n", data->str);
    return data->i1 + data->i2;
}

python code

from ctypes import *

core = CDLL('core.dll')

add_val = core.add(1, 2)
multi_val = core.multi(2, 3)

print(add_val)
print(multi_val)

class CoreData(Structure):
    _fields_ = [("i1", c_int),
                ("i2", c_int),
                ("str", c_char*20)]

coredata = CoreData()
coredata.i1 = 10
coredata.i2 = 20
coredata.str = b"hello world"
coredata_ptr = byref(coredata)
struct_add_val = core.struct_add(coredata_ptr)

print(struct_add_val)

result

3
6
30
hello world

C call python function

c calls python, which needs to be increased and python36.lib, sometimes when you need python36_d.lib when compiling, you just need to copy and rename python36.lib to python36_d.lib and put it in the same directory

python code

def py_print():
    print("py_print")

def py_add(a,b):
    return a+b

c code

#include "stdio.h"
#include "windows.h"
#include <Python.h>   

void main()
{
    Py_Initialize();                  
    PyObject* pModule = NULL;        
    PyObject* pFunc = NULL;        
    PyObject* pArgs = NULL;
    PyObject* pValue = NULL;

    pModule = PyImport_ImportModule("python_demo");          
    pFunc = PyObject_GetAttrString(pModule, "py_print");   
    PyEval_CallObject(pFunc, NULL);   

    pFunc = PyObject_GetAttrString(pModule, "py_add");
    pArgs = PyTuple_New(2);

    PyTuple_SetItem(pArgs, 0, Py_BuildValue("i", 5));
    PyTuple_SetItem(pArgs, 1, Py_BuildValue("i", 10));

    pValue = PyEval_CallObject(pFunc, pArgs);
    int res = 0;
    PyArg_Parse(pValue, "i", &res);
    printf("res %d\n", res);

    Py_Finalize();   
    return;
}

result

py_print
res 15