Qt调用dll

清疚 2022-05-10 00:40 264阅读 0赞

**直接上代码**

extern "C"{
    DLLSHARED_EXPORT Dll* getDllObject(); //获取类Dll的对象
    DLLSHARED_EXPORT void releseDllObject(Dll*); //获取类Dll的对象
    
    DLLSHARED_EXPORT void helloWorld();
    DLLSHARED_EXPORT int add(int a,int b);
    }

#include "mainwindow.h"
    #include <QApplication>
    #include <iostream>
    #include <QLibrary>
    #include <windows.h>
    #include "dll.h"  //头文件还是需要加的，否则无法解析Dll类
    
    typedef Dll* (*CreatDll)();//定义函数指针,获取类Dll对象;
    typedef bool (*ReleseDll)(Dll*);
    typedef void (*fun)();
    
    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv);
        MainWindow w;
        w.show();
    
        QLibrary mylib("dll.dll");   //声明所用到的dll文件
        //判断是否正确加载
        if (mylib.load())
        {
            std::cout << "DLL  loaded!"<<std::endl;
            CreatDll creatDll = (CreatDll)mylib.resolve("getDllObject");
            ReleseDll decDll=(ReleseDll)mylib.resolve ("releseDllObject");
            fun hello=(fun)mylib.resolve ("helloWorld");
            if(hello)hello();
            if(creatDll&&decDll)
            {
                Dll *testDll = creatDll();
                testDll->GetStrAdd ("abc","ABD");
                testDll->Print ();
                decDll(testDll);
            }
        }
        //加载失败
        else
            std::cout << "DLL is not loaded!"<<std::endl;
    
        mylib.unload ();
    
        return a.exec();
    }

**工程文件加入**

#LIBS += "D:/qt_work/build-dllTest-Desktop_Qt_5_11_1_MinGW_32bit-Debug/debug/dll.dll" 或者
    LIBS += D:\qt_work\build-dllTest-Desktop_Qt_5_11_1_MinGW_32bit-Debug\debug\dll.dll

`否则会报错：`

D:\qt_work\build-dllTest-Desktop_Qt_5_11_1_MinGW_32bit-Debug\debug\main.o:-1: In function
      `Z5qMainiPPc':
    D:\qt_work\dllTest\main.cpp:30: error: undefined reference to
      `_imp___ZN3Dll9GetStrAddENSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES5_'
    D:\qt_work\dllTest\main.cpp:31: error: undefined reference to `_imp___ZN3Dll5PrintEv'