22.dll调用技术

1.dll文件:

 1 #include <Windows.h>
 2 
 3 _declspec(dllexport) void message_hello()
 4 {
 5     MessageBoxA(0, "hello", "hello", 0);
 6 }
 7 
 8 _declspec(dllexport) double add(double num1, double num2)
 9 {
10     return num1 + num2;
11 }

2.调用dll文件

#include <stdlib.h>
#include <Windows.h>

void main()
{
    HMODULE mod = LoadLibraryA("工具.dll");
    if (mod == NULL)
    {
        printf("load error
");
        exit(0);
    }

    //获取函数地址
    void(*message_hello)() = (void(*)())GetProcAddress(mod, "message_hello");
    double(*add)(double, double) = (double(*)(double, double))GetProcAddress(mod, "add");

    //调用函数
    if (message_hello == NULL)
    {
        printf("find error
");
    }
    else
    {
        message_hello();
    }

    if (add == NULL)
    {
        printf("find error
");
    }
    else
    {
        printf("%f",add(1,3));
    }
    system("pause");
}

运行截图: