Programming

/*
sum.c
*/

#include <stdlib.h>
#include <stdio.h>


int sum(int a, int b)
{
  int c;
  c = a+b;
  return(c);
}

/*
product.c
*/

#include <stdio.h>

int product(int a, int b)
{
  int product = 0;
  while(b>0)
  {
    product = sum(product, a);
    b--;
  }
  return(product);
}

/*
product_main_dyn.c
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>

int
main(int argc, char **argv)
{

  int a;
  int b;
  int ris;
  void *hdl_prd;
  void *hdl_smm;
  int (*prod)(int, int);
  char *error;

  if(argc != 3)
  {
    printf("insert two int number to run\n");
    exit(EXIT_FAILURE);
  }
  
  a = atoi(argv[1]);
  b = atoi(argv[2]);
  

  hdl_prd = dlopen("/home/shade82/product/libproduct.so.1", (RTLD_LAZY));
  if (!hdl_prd) 
  {
    printf("error open library\n");
    exit(EXIT_FAILURE);
  }
  dlerror();  
  
  *(void **) (&prod) = dlsym(hdl_prd, "product");
  if ((error = dlerror()) != NULL)  
  {
    printf("error: not resolve symbol\n");
    exit(EXIT_FAILURE);
  }
  
  ris = (*prod)(a,b);
  printf("product: %d\n",ris);
  dlclose(hdl_prd);
  exit(EXIT_SUCCESS);
}

#! /bin/bash

rm *.o *.exe libsum.so.1 libproduct.so.1 libsum.so.1.0.0 libproduct.so.1.0.0
gcc -fPIC -c sum.c
gcc -fPIC -c product.c
gcc -shared -Wl,-soname,libsum.so.1 -o libsum.so.1.0.0 sum.o -lc
gcc -shared -Wl,-soname,libproduct.so.1 -o libproduct.so.1.0.0 product.o -lc
export LD_LIBRARY_PATH=/home/shade82/
sudo ldconfig -n .
gcc prod_main_dyn.c -o prod_main_dyn.exe -ldl