Why such small program don't send nothing through com-port?

But I have program, which send data with similar connection paremeters normally. What is problem?

Code:

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// Temp.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "Temp.h"

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;                                                                // current instance
TCHAR szTitle[MAX_LOADSTRING];                                        // The title bar text
TCHAR szWindowClass[MAX_LOADSTRING];                        // the main window class name

// Forward declarations of functions included in this code module:
ATOM                                MyRegisterClass(HINSTANCE hInstance);
BOOL                                InitInstance(HINSTANCE, int);
LRESULT CALLBACK        WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK        About(HWND, UINT, WPARAM, LPARAM);
HANDLE hComPort;
BYTE Eof;
BYTE STX;
DWORD InitPort()
{
        hComPort = INVALID_HANDLE_VALUE;
        // открыть порт . . .
        hComPort = CreateFile(L"COM3",                        // порт
          GENERIC_READ | GENERIC_WRITE,                //чтение и запись
          0,                                                // must be opened with exclusive-access
          NULL,                                                // default security // no security attributes
          OPEN_EXISTING,                        // existing file only
          FILE_ATTRIBUTE_NORMAL,        //FILE_ATTRIBUTE_NORMAL, FILE_FLAG_OVERLAPPED,        //? normal file  // not overlapped I/O == 0, 
          NULL);                                        // no attr. template // hTemplate must be NULL for comm devices
        if (hComPort == INVALID_HANDLE_VALUE)
        {
                DWORD err = GetLastError();
                CloseHandle(hComPort);
                return err;
        }
        DCB dcb;
        COMMTIMEOUTS PortTimeOuts;
        // настройки порта . . .
        if (!GetCommState(hComPort, &dcb))
        {
                DWORD err = GetLastError();
                CloseHandle(hComPort);
                return err;
        }
        dcb.BaudRate = CBR_9600;    // set the baud rate CBR_9600
        dcb.ByteSize = 8;            // data size, xmit, and rcv
        dcb.Parity = NOPARITY;        // no parity bit
        dcb.StopBits = TWOSTOPBITS;    // one stop bit
        if (!SetCommState(hComPort, &dcb))
        {
                DWORD err = GetLastError();
                CloseHandle(hComPort);
                return err;
        }
    SetupComm(hComPort, 1024*1024, 1024*1024);
        // таймауты ввода-вывода . . .
        if (!GetCommTimeouts(hComPort, &PortTimeOuts))
        {
                DWORD err = GetLastError();
                CloseHandle(hComPort);
                return err;
        }
        PortTimeOuts.ReadIntervalTimeout                = 5;
        PortTimeOuts.ReadTotalTimeoutMultiplier  = 5;
        PortTimeOuts.ReadTotalTimeoutConstant    = 2000;
        PortTimeOuts.WriteTotalTimeoutMultiplier = 0;
        PortTimeOuts.WriteTotalTimeoutConstant  = 0;
       
        if (!SetCommTimeouts(hComPort, &PortTimeOuts))
        {
                DWORD err = GetLastError();
                CloseHandle(hComPort);
                return err;
        }
        PurgeComm( hComPort, PURGE_RXCLEAR );                //Очистить буфер драйвера на приём
        return 0;

}

void TempWrite()
{

 if (InitPort())
  {
        //MessageBox(hwnd,L"Ошибка открытия порта", L"Ошибка", 0);       
        //Writing = FALSE;
    return;   
  }
 Sleep(400);
 DWORD Written;
                  char b='a';
          BYTE *arr = new BYTE[256];
                arr[0] = 3;
                arr[1] = '\0';
                arr[2] = STX;
                arr[3] = '\0';
                arr[4] = 4;
                arr[5] = Eof;
                WriteFile(hComPort, arr, 256, &Written, NULL);
      CloseHandle(hComPort);
 }

int APIENTRY _tWinMain(HINSTANCE hInstance,
                    HINSTANCE hPrevInstance,
                    LPTSTR    lpCmdLine,
                    int      nCmdShow)
{
        UNREFERENCED_PARAMETER(hPrevInstance);
        UNREFERENCED_PARAMETER(lpCmdLine);

        // TODO: Place code here.
        MSG msg;
        HACCEL hAccelTable;

        // Initialize global strings
        LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
        LoadString(hInstance, IDC_TEMP, szWindowClass, MAX_LOADSTRING);
        MyRegisterClass(hInstance);

        // Perform application initialization:
        if (!InitInstance (hInstance, nCmdShow))
        {
                return FALSE;
        }

        hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_TEMP));
    TempWrite();
        // Main message loop:
        while (GetMessage(&msg, NULL, 0, 0))
        {
                if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
                {
                        TranslateMessage(&msg);
                        DispatchMessage(&msg);
                }
        }

        return (int) msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
//  COMMENTS:
//
//    This function and its usage are only necessary if you want this code
//    to be compatible with Win32 systems prior to the 'RegisterClassEx'
//    function that was added to Windows 95. It is important to call this function
//    so that the application will get 'well formed' small icons associated
//    with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
        WNDCLASSEX wcex;

        wcex.cbSize = sizeof(WNDCLASSEX);

        wcex.style                        = CS_HREDRAW | CS_VREDRAW;
        wcex.lpfnWndProc        = WndProc;
        wcex.cbClsExtra                = 0;
        wcex.cbWndExtra                = 0;
        wcex.hInstance                = hInstance;
        wcex.hIcon                        = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_TEMP));
        wcex.hCursor                = LoadCursor(NULL, IDC_ARROW);
        wcex.hbrBackground        = (HBRUSH)(COLOR_WINDOW+1);
        wcex.lpszMenuName        = MAKEINTRESOURCE(IDC_TEMP);
        wcex.lpszClassName        = szWindowClass;
        wcex.hIconSm                = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

        return RegisterClassEx(&wcex);
}

//
//  FUNCTION: InitInstance(HINSTANCE, int)
//
//  PURPOSE: Saves instance handle and creates main window
//
//  COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
  HWND hWnd;

  hInst = hInstance; // Store instance handle in our global variable

  hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

  if (!hWnd)
  {
      return FALSE;
  }

  ShowWindow(hWnd, nCmdShow);
  UpdateWindow(hWnd);

  return TRUE;
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND        - process the application menu
//  WM_PAINT        - Paint the main window
//  WM_DESTROY        - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
        int wmId, wmEvent;
        PAINTSTRUCT ps;
        HDC hdc;

        switch (message)
        {
        case WM_COMMAND:
                wmId    = LOWORD(wParam);
                wmEvent = HIWORD(wParam);
                // Parse the menu selections:
                switch (wmId)
                {
                case IDM_ABOUT:
                        DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                        break;
                case IDM_EXIT:
                        DestroyWindow(hWnd);
                        break;
                default:
                        return DefWindowProc(hWnd, message, wParam, lParam);
                }
                break;
        case WM_PAINT:
                hdc = BeginPaint(hWnd, &ps);
                // TODO: Add any drawing code here...
                EndPaint(hWnd, &ps);
                break;
        case WM_DESTROY:
                PostQuitMessage(0);
                break;
        default:
                return DefWindowProc(hWnd, message, wParam, lParam);
        }
        return 0;
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
        UNREFERENCED_PARAMETER(lParam);
        switch (message)
        {
        case WM_INITDIALOG:
                return (INT_PTR)TRUE;

        case WM_COMMAND:
                if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
                {
                        EndDialog(hDlg, LOWORD(wParam));
                        return (INT_PTR)TRUE;
                }
                break;
        }
        return (INT_PTR)FALSE;
}

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Did you debug your "small" program?
Is the TempWrite() called? If "YES" then what does WriteFile return?

VictorN, called and success

Then what is the value of Written

VictorN, 256

Quote:

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Originally Posted by AKE

VictorN, 256

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But it means that this program does send data to your com3 port!
So why do you complain? :confused:

VictorN, program on other computer don't catch this data, inspite of similar program send normally. I think problem in my program.

But first thing in such a case would be to check a cable.
The second one - test your sender program with a null-modem cable using hyperterminal, then - check Windows firewall on both computers...

Big sorry, I sent it on other port...

VictorN, Thanks...