一个调试打印功能来统治它们 [英] One Debug-Print function to rule them all

问题描述

我在这种情况下，我有几个不同的结构，在我的代码，我想打印到控制台。

I'm in the situation that i have several different structs around in my code, that i want to print to the console.

三个例子

typedef struct ReqCntrlT    /* Request control record */
{
int             connectionID;
int             dbApplID;
char            appDescr[MAX_APPDSCR];
int             reqID;
int         resubmitFlag;
unsigned int    resubmitNo;
char            VCIver[MAX_VCIVER];
int             loginID;

}   ReqCntrlT;

//---------------------------------------------   

typedef struct      /* Connection request data block */
{
    char            userID[MAX_USRID];
    char            password[MAX_PWDID];

}   CnctReqDataT;

//---------------------------------------------   

typedef struct {
    char            userID[LOGIN_MAX_USERID];
    char            closure;
    int             applVersion;
    int             authorizationDataLength;
    void            *authorizationData; }   LoginReqDataT;

所以我想要的是一个调试函数，它只需要一个struct作为参数，所有成员的结构，如此：

So what i want to have, is a debug function that simply takes a struct as Parameter and puts out all members of the struct, as so:

LoginReqDataT* foo = new LoginReqDataT;
foo->applVersion = 123;
//...
debugPrintMe(foo);

CnctReqDataT* bar = new CnctReqDataT;
strcpy(bar->userID, "123");
strcpy(bar->password, "mypwd");
debugPrintMe(bar);

我目前拥有的是一个无尽的函数，它是这样的东西：

What I currently have, is an endless function which is doing stuff like this:

template <class T>
void debugPrintMe(T myvar)
{
    if (!DEBUG) return;

    if (typeid(T) == typeid(ReqCntrlT*))
    {
        ReqCntrlT* r = (ReqCntrlT*)myvar; 
        cout << "reqControl: " << endl 
             << "\tconnectionID: " << r->connectionID << endl
             << "\tdbApplID: " << r->dbApplID << endl
             //...
             << "\tloginID: " << r->loginID << endl << endl;
    }
    else if (typeid(T) == typeid(CallBkAppDataT*))
    {
        CallBkAppDataT* c = (CallBkAppDataT*)myvar; 
        cout << "appData: " << endl
             << "\tappRespBlockSize " << c->appRespBlockSize << endl
             //...
             << "\tstreamType: " << c->streamType << endl << endl;
    }
    //... and so on
}

Is there a more elegant way to do this?

推荐答案

是的，有一个更优雅的方式来做这个code> ... else if（typeid（T）== ... ？Yuck！）你可以写一些 operator< / code>你的结构 s。这使得你的 debugPrintMe（）函数nice和generic允许您将结构流传输到 cout ， cerr ，记录器， ostringstream ，...

Yes there most certainly is a more elegant way of doing this (... else if (typeid(T) == ...? Yuck!). You could write some operator <<()s for your structs. This makes your debugPrintMe() function nice and generic and also allows you to stream your structs to cout, cerr, a logger, an ostringstream, ...

这是一个让你开始的例子：

Here's an example to get you started:

std::ostream& operator <<(std::ostream& os, const ReqCntrlT& r)
{
    os << "reqControl"
        << "\n\tconnectionID: " << r.connectionID 
        << "\n\tdbApplID: " << r.dbApplID 
        << "\n\tappDescr: " << r.appDescr
        << "\n\treqID: " << r.reqID
        << "\n\tresubmitFlag: " << r.resubmitFlag
        << "\n\tresubmitNo: " << r.resubmitNo
        << "\n\tVCIver: " << r.VCIver
        << "\n\tloginID: " << r.loginID
        << '\n';
    return os;
}

template <class T>
void debugPrintMe(const T& myvar)
{
    if (DEBUG)
    {
        std::cout << myvar << std::endl;
    }
}

int main()
{
    ReqCntrlT r;

    // [...]

    debugPrintMe(r);

    return 0;
}

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