Reading DATA from Magnetic card reader MT188 using C++

Question

Im trying to read the data from a magnetic card reader its model is MT188. The Card reader comes with a DLL and a doc for the functions in the DLL. the process to read a card is as follows.

HANDLE APIENTRY CommOpenWithBaut(UINT nPort, UINT _data) 

open serial Communications example : CommOpenWithBaut(1,9600);.

int APIENTRY CarderCheckSt(HANDLE hComHandle, unsigned char &PewSt, unsigned char &CardType, unsigned char &CardSt, unsigned char &PowerSt) 

check Device status.

int APIENTRY MagRead(HANDLE hComHandle,BYTE *MagData,int &lenth) 

read Magnetic card data

int APIENTRY CommClose(HANDLE hComHandle); 

Close port after the card is read.

Each function has a return value. This is an example of the cout<<Magread<<endl; is gives a value of 00007FF792E41258. What am I doing wrong? How can I use these functions the right way?

here is my main.

int main(int arg, char* argc[])
{
    CommOpenWithBaut(1,9600);
    cout<< "This is the cards data:  " << MagRead << endl;
    cout << "This is the cards status:  " << CarderCheckSt << endl;
    CommClose;
}

updates:

I receive this error when I try to run the program:

LNK2019 unresolved external symbol "__declspec(dllimport) void * __cdecl CommOpenWithBaut(unsigned int,unsigned int)" (__imp_?CommOpenWithBaut@@YAPEAXII@Z) referenced in function main 

This is my header file:

#include <iostream>
#include <windows.h>

#ifdef Modulev188_EXPORTS
#define Modulev188_API __declspec(dllexport)
#else
#define Modulev188_API __declspec(dllimport)
#endif

Modulev188_API HANDLE  CommOpenWithBaut(UINT nPort, UINT _data);
Modulev188_API int  CommClose(HANDLE hComHandle);
Modulev188_API int  CarderCheckSt(HANDLE hComHandle, unsigned char& PewSt, unsigned char& CardType, unsigned char& CardSt, unsigned char& PowerSt);
Modulev188_API int  CarderVersion(HANDLE hComHandle, unsigned char* VersionNo, int& lenth);
//DLLEXPORT int WINAPI ContactCPU_ColdReset(HANDLE hComHandle, BYTE* _CPUTYPE, BYTE* _exData, int* _exdataLen);
//DLLEXPORT int WINAPI ContactCPU_Dormancy(HANDLE hComHandle);
Modulev188_API int  ContactCPU_CAPDU(HANDLE hComHandle, int _dataLen, BYTE* _APDUData, BYTE* _exData, int* _exdataLen);
Modulev188_API int  SIM_Reset(HANDLE hComHandle, BYTE _VOLTAGE, BYTE _SIMNo, BYTE& _SIMTYPE, BYTE* _exData, int& _exdataLen);
Modulev188_API int  SIM_C_APDU(HANDLE hComHandle, BYTE SIMNo, int _dataLen, BYTE* _APDUData, BYTE* _exData, int& _exdataLen);
Modulev188_API int  SIM_CardClose(HANDLE hComHandle);
Modulev188_API int  MagRead(HANDLE hComHandle, BYTE* MagData, int& lenth);
Modulev188_API int  MagCleaner(HANDLE hComHandle);

Answer 1

You're not actually calling MagRead, CarderCheckSt or CommClose because you aren't invoking them as functions with parentheses and parameters. You're just printing them out as function pointers, so the values you see represent the address of the function entry point.

Instead, you need to provide suitable parameters to each function. From the 'open' function you will get a handle that you pass to all subsequent functions.

#include <iostream>

extern "C" {    
    #include <mt188.h> // The header for your C library
}

using namespace std;

int main(int argc, char* argv[])
{
    // Open the device

    HANDLE port = CommOpenWithBaut(1, 9600);

    if (port == 0)
    {
        cerr << "Cannot open device";
        return -1;
    }

    // Read status

    unsigned char PewSt = 0;
    unsigned char CardType = 0;
    unsigned char CardSt = 0;
    unsigned char PowerSt = 0;

    int rc = CarderCheckSt(port, PewSt, CardType, CardSt, PowerSt);

    // Read buffer of data

    int bufferSize = 128;
    BYTE buffer[bufferSize];

    int bytesRead = MagRead(port, buffer, bufferSize);

    //

    CommClose(port);

    return 0;
}