Cleaned up code of ctypes_and_api. will serve as the example for the...

Cleaned up code of ctypes_and_api. will serve as the example for the implementation in the python-binaryc

ctypes_and_api/demolib.c

 #include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
 #include "demolib.h"
 
-
 typedef double (*fn_def)(double, double);
 
-int add_number_using_pointer(int (*pf)(int, int), int number_1, int number_2) {
-    int result;
-    result = pf(number_1, number_2);
-    return result;
-}
-
-double calc_mean_using_pointer(long int str_1, double number_1, double number_2)
+double run_function_via_pointer(long int str_1, double number_1, double number_2)
 {
-    printf("test for running function with mem addr %ld with arguments %f %f\n", str_1, number_1, number_2);
-    
+    // Function that recieves a long int containing the memory adress of a function, and two values
+    // the long int will be interpreted as a pointer, and the two values will be passed to this function
+    // will work as long as the function of which the memory adress is given accepts two doubles and returns a double
+
     // convert into pointer
     fn_def fnptr = (fn_def)str_1;
 
-    printf("size of function pointer %zu\n",sizeof(fnptr));
-    printf("%p size: %zu\n", fnptr, sizeof(fnptr));
-
-    double result;
-    result = fnptr(number_1, number_2);
+    // print some stuff
+    // printf("test for running function with mem addr %ld with arguments %f %f\n", str_1, number_1, number_2);
+    // printf("size of function pointer %zu\n",sizeof(fnptr));
+    // printf("%p size: %zu\n", fnptr, sizeof(fnptr));
 
+    double result = fnptr(number_1, number_2);
     return result;
-}
-
-double test_func(char* str_1, double number_1, double number_2) {
-    // double result;
-    // result = pf(number_1, number_2);
-    printf("test for running function with mem addr %s with arguments %f %f\n", str_1, number_1, number_2);
-    return 6.5;
 }
\ No newline at end of file

ctypes_and_api/demolib.h

-// Example header file
-
+double run_function_via_pointer(long int str_1, double number_1, double number_2);
\ No newline at end of file
-// char construct_string(int number);
-double calc_mean_using_pointer(long int str_1, double number_1, double number_2);
-double test_func(char* str_1, double number_1, double number_2);
\ No newline at end of file

ctypes_and_api/demomodule.c

@@ -2,48 +2,26 @@
 #include <Python.h>
 #include "demolib.h"
 
-
-// https://stackoverflow.com/questions/51505391/how-to-parse-void-to-pyobject
-
-static PyObject *DemoLib_CalcMeanWithPointerTest(PyObject *self, PyObject *args) {
-    char *str_1;
-    double number_1;
-    double number_2;
-    if (!PyArg_ParseTuple(args, "sdd", &str_1, &number_1, &number_2)) {
-        return NULL;
-    }
-    
-    double result;
-    result = test_func(str_1, number_1, number_2);
-    return Py_BuildValue("d", result);
-}
-
-
-static PyObject *DemoLib_CalcMeanWithPointer(PyObject *self, PyObject *args) {
+// Declare the function wrapping the python call and the c function
+static PyObject *DemoLib_RunFunctionViaPointer(PyObject *self, PyObject *args) {
     long int str_1;
     double number_1;
     double number_2;
     if (!PyArg_ParseTuple(args, "ldd", &str_1, &number_1, &number_2)) {
         return NULL;
     }
+    // printf("%p contents %ld\n", &str_1, str_1);
     
     double result;
-    printf("%p contents %ld\n", &str_1, str_1);
-    result = calc_mean_using_pointer(str_1, number_1, number_2);
+    result = run_function_via_pointer(str_1, number_1, number_2);
     return Py_BuildValue("d", result);
 }
 
 // module's function table
 static PyMethodDef DemoLib_FunctionsTable[] = {
     {
-        "calc_mean_with_pointer", // name exposed to Python
-        DemoLib_CalcMeanWithPointer, // C wrapper function
-        METH_VARARGS, // received variable args (but really just 1)
-        "Calculate the mean of two values via a pointer function" // documentation
-    }, 
-    {
-        "calc_mean_with_pointer_test", // name exposed to Python
-        DemoLib_CalcMeanWithPointerTest, // C wrapper function
+        "run_function_via_pointer", // name exposed to Python
+        DemoLib_RunFunctionViaPointer, // C wrapper function
         METH_VARARGS, // received variable args (but really just 1)
         "Calculate the mean of two values via a pointer function" // documentation
     }, 

ctypes_and_api/main.py

 import ctypes
 import os
 import subprocess 
-  
-from functions import loadLibraryFunction, buildLibrary
-
-import demo
 
+import demo # load library with the C-interfacing
 
+from functions import loadLibraryFunction, buildLibrary
 
+# Build shared library
 buildLibrary()
 
-# Loading library
+# Loading shared library
 libmean = ctypes.CDLL("libmean.so.1") # loads the shared library
 
 # Get memory adress of function. mimicking a pointer
-mem = ctypes.cast(libmean.mean, ctypes.c_void_p).value
-print("mem adress of mean function {}, type: {}".format(mem, type(mem)))
+mem_mean_function = ctypes.cast(libmean.mean, ctypes.c_void_p).value
+print("mem adress of mean function {}, type: {}".format(mem_mean_function, type(mem_mean_function)))
+
+mem_product_function = ctypes.cast(libmean.product, ctypes.c_void_p).value
+print("mem adress of product function {}, type: {}".format(mem_product_function, type(mem_product_function)))
+
+mem_sum_function = ctypes.cast(libmean.sum, ctypes.c_void_p).value
+print("mem adress of sum function {}, type: {}".format(mem_sum_function, type(mem_sum_function)))
+
+print('\n\n')
+
+result_mean = demo.run_function_via_pointer(mem_mean_function, 10, 2.0)
+print("Result of mean: {}\n".format(result_mean))
 
+result_product = demo.run_function_via_pointer(mem_product_function, 10, 2.0)
+print("Result of product: {}\n".format(result_product))
 
-dong = demo.calc_mean_with_pointer(mem, 1.0, 2.0)
-print(dong)
+result_sum = demo.run_function_via_pointer(mem_sum_function, 10, 2.0)
+print("Result of sum: {}\n".format(result_sum))
\ No newline at end of file

ctypes_and_api/mean.c

@@ -3,18 +3,23 @@
 #include <stdlib.h>
 #include <math.h>
 
-double mean(double a, double b) {
-  printf("calculating mean with %f and %f", a, b);
-  return (a+b)/2;
+double mean(double a, double b)
+{
+  printf("calculating mean of %f and %f\n", a, b);
+  double mean = (a+b)/2.0;
+  return mean;
 }
 
-void print_pointer_to_mean() {
-    printf("pointer to mean function (via c code): %p\n", &mean);
+double product(double a, double b)
+{
+    printf("Calculating product of %f and %f\n", a, b);
+    double product = a * b;
+    return product;
 }
 
-double calc_mean_using_pointer(double (*pf)(double, double), double number_1, double number_2) {
-    double result;
-    result = pf(number_1, number_2);
-    printf("result running mean function with pointer to the function: %f", result);
-    return result;
+double sum(double a, double b)
+{
+    printf("Calculating sum of %f and %f\n", a, b);
+    double sum = a + b;
+    return sum;
 }
\ No newline at end of file

ctypes_and_api/mean.h

-// Returns the mean of passed parameters
 double mean(double, double);
-void print_pointer_to_get_value();
-double calc_mean_using_pointer(double (*pf)(double, double), double number_1, double number_2);
+double product(double, double);
+double sum(double, double);
\ No newline at end of file

ctypes_and_api/readme.org

@@ -17,14 +17,11 @@ then run python main.py
 
 
 * Some leads:
-
-# https://solarianprogrammer.com/2019/07/18/python-using-c-cpp-libraries-ctypes/
-# https://gist.github.com/elyezer/7099291
-
-# https://www.geeksforgeeks.org/turning-a-function-pointer-to-callable/
-# https://stackoverflow.com/questions/9420673/is-it-possible-to-compile-c-code-using-python
-# https://documentation.help/Python-3.2.1/ctypes.html
-
-# https://stackoverflow.com/questions/49635105/ctypes-get-the-actual-address-of-a-c-function
+- https://solarianprogrammer.com/2019/07/18/python-using-c-cpp-libraries-ctypes/
+- https://gist.github.com/elyezer/7099291
+- https://www.geeksforgeeks.org/turning-a-function-pointer-to-callable/
+- https://stackoverflow.com/questions/9420673/is-it-possible-to-compile-c-code-using-python
+- https://documentation.help/Python-3.2.1/ctypes.html
+- https://stackoverflow.com/questions/49635105/ctypes-get-the-actual-address-of-a-c-function
+- https://blog.regehr.org/archives/1621
+- https://www.oreilly.com/library/view/understanding-and-using/9781449344535/ch01.html
\ No newline at end of file
-# https://blog.regehr.org/archives/1621
-# https://www.oreilly.com/library/view/understanding-and-using/9781449344535/ch01.html
\ No newline at end of file