mr4th-dynamic-linking/win32_linking/win32_base.c

// declare base_func; mark it as an exported symbol
__declspec(dllexport) void base_func(void);

// define base_func
#include <stdio.h>
int x = 0;
__declspec(dllexport) void
base_func(void){
  printf("x = %d\n", x);
  x += 1;
}