Windows下C语言调用dll动态链接库

#include "stdio.h"

_declspec(dllexport) void test_print(char const *str)
{
    printf("%s\n", str);
}

_declspec(dllexport) int test_add(int a, int b)
{
    return a + b;
}

#include <stdlib.h>
#include <windows.h>

int main(int argc, char const *argv[])
{
    // define two functional pointer
    void(*p_test_print)(char const *) = NULL;
    int(*p_test_add)(int, int) = NULL;

    int add_result;

    // load dll file, require window.h file
    HMODULE module = LoadLibraryA("hello_dll.dll");
    if (module == NULL) {
        system("error load");
    }
    p_test_print = (void(*)(char const *))GetProcAddress(module, "test_print");
    p_test_add = (int(*)(int, int))GetProcAddress(module, "test_add");
    if (p_test_print != NULL) {
        p_test_print("Hello This is from dll");
    } else {
        system("function p_test_print can not excute");
    }
    if (p_test_add != NULL) {
        add_result = p_test_add(5, 5);
        printf("Add result is %d\n", add_result);
    } else {
        system("function p_test_print can not excute");
    }
    FreeLibrary(module);
    system("pause");
    return 0;
}