CODEWITHSUNDEEP
cwinapifile-ioserial-port
Kumaa
Kumaa

Reputation: 31

function with WriteFile- writing to serial port

I want to include writeFile function of serial port wtiting to a fuctiona and call that function several time. I wrote following code. But function is returning false. I could not find any error.

bool WriteBuffer (char *lpBuf,DWORD dwToWrite){

//  DWORD dwBytesWritten;
//  DWORD dwToWrite;
printf("%s", lpBuf);

 if(!WriteFile(hSerial, lpBuf, sizeof(lpBuf) ,&dwBytesWritten, NULL))

        { 

        FormatMessage(
        FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        GetLastError(),
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPWSTR)&lastError,
        1024,
        NULL);

    CloseHandle(hSerial);
    hSerial=NULL;
    printf("ERROR in WRITE FILE \n");
    return false;
//Handle Error Condition
}
printf("You wrote'%s'",lpBuf);


 return true;
 }

Upvotes: 0

Views: 1375

Answers (1)

David Heffernan
David Heffernan

Reputation: 612954

You are passing sizeof(lpBuf) to the nNumberOfBytesToWrite parameter. But sizeof(lpBuf) is simply the size of a pointer. You should be passing dwToWrite I presume.

If that doesn't solve your problem then the other cause of errors in hSerial not being valid.

Having gone to all the trouble of calling GetLastError and FormatMessage, it would have been helpful if you had told us what those functions returned.

Upvotes: 1

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