c++回调

c++回调包含类函数回调和非类函数回调。

类函数回调，函数指针指向函数名称，需要带类作用域，调用时需要用到类指针。

如qt里面定义一个返回值为qbytearray的函数指针，

 typedef QByteArray (myThead::*Func_Construct)(QByteArray line);//定义函数指针

    QByteArray deviceStatus_construct(QByteArray);
    QByteArray realData_construct(QByteArray line);
    QByteArray dayRun_construct(QByteArray);
    QByteArray monthCheck_construct(QByteArray line);
    QByteArray flag_construct(QByteArray line);
    QByteArray palarm_construct(QByteArray line);
    QByteArray deviceDefine_construct(QByteArray line);
    QByteArray staff_construct(QByteArray line);
    QByteArray deviceStatus_construct_str(QString line);

   case e_deviceStatus:
        pFunc = &myThead::deviceStatus_construct;
        break;
    case e_realData:
        pFunc = &myThead::realData_construct;
        break;
    case e_dayRun:
        pFunc = &myThead::dayRun_construct;
        break;
    case e_monthCheck:
        pFunc = &myThead::monthCheck_construct;
        break;
    case e_flag:
        pFunc = &myThead::flag_construct;
        break;
    case e_palarm:
        pFunc = &myThead::palarm_construct;
        break;
    case e_deviceDefine:
        pFunc = &myThead::deviceDefine_construct;
        break;
    case e_staff:
        pFunc = &myThead::staff_construct;

回调：
QByteArray btLine = (this->*pFunc)(strLine.toUtf8());

非类指针则简单得多：

typedef void (*Func)(int ,int )
void func1(int numA,int numB){
     printf(numA+numB);      
}

void func2(int numA,int numB){
   printf(numA - numB);      
}

int main(){
     int numA = 10;
    int numB=5;  
      Func pFunc = &func1;
     pFunc (numA ,numB);
     pFunc = &func2;
     pFunc(numA,numB);
    return0;
}