Reading Input Buffer Events

The ReadConsoleInput function can be used to directly access a console's input buffer. When a console is created, mouse input is enabled and window input is disabled. To ensure that the process receives all types of events, this example uses the SetConsoleMode function to enable window and mouse input. Then it goes into a loop that reads and handles 100 console input events. For example, the message "Keyboard event" is displayed when the user presses a key and the message "Mouse event" is displayed when the user interacts with the mouse.


#include <windows.h>
#include <stdio.h>

HANDLE hStdin; 
DWORD fdwSaveOldMode;

VOID ErrorExit(LPSTR);
VOID KeyEventProc(KEY_EVENT_RECORD); 
VOID MouseEventProc(MOUSE_EVENT_RECORD); 
VOID ResizeEventProc(WINDOW_BUFFER_SIZE_RECORD); 
 
int main(VOID) 
{ 
    DWORD cNumRead, fdwMode, i; 
    INPUT_RECORD irInBuf[128]; 
    int counter=0;
 
    // Get the standard input handle. 
 
    hStdin = GetStdHandle(STD_INPUT_HANDLE); 
    if (hStdin == INVALID_HANDLE_VALUE) 
        ErrorExit("GetStdHandle"); 
 
    // Save the current input mode, to be restored on exit. 
 
    if (! GetConsoleMode(hStdin, &fdwSaveOldMode) ) 
        ErrorExit("GetConsoleMode"); 

    // Enable the window and mouse input events. 
 
    fdwMode = ENABLE_WINDOW_INPUT | ENABLE_MOUSE_INPUT; 
    if (! SetConsoleMode(hStdin, fdwMode) ) 
        ErrorExit("SetConsoleMode"); 
 
    // Loop to read and handle the next 100 input events. 
 
    while (counter++ <= 100) 
    { 
        // Wait for the events. 
 
        if (! ReadConsoleInput( 
                hStdin,      // input buffer handle 
                irInBuf,     // buffer to read into 
                128,         // size of read buffer 
                &cNumRead) ) // number of records read 
            ErrorExit("ReadConsoleInput"); 
 
        // Dispatch the events to the appropriate handler. 
 
        for (i = 0; i < cNumRead; i++) 
        {
            switch(irInBuf[i].EventType) 
            { 
                case KEY_EVENT: // keyboard input 
                    KeyEventProc(irInBuf[i].Event.KeyEvent); 
                    break; 
 
                case MOUSE_EVENT: // mouse input 
                    MouseEventProc(irInBuf[i].Event.MouseEvent); 
                    break; 
 
                case WINDOW_BUFFER_SIZE_EVENT: // scrn buf. resizing 
                    ResizeEventProc( irInBuf[i].Event.WindowBufferSizeEvent ); 
                    break; 
 
                case FOCUS_EVENT:  // disregard focus events 
 
                case MENU_EVENT:   // disregard menu events 
                    break; 
 
                default: 
                    ErrorExit("Unknown event type"); 
                    break; 
            } 
        }
    } 

    // Restore input mode on exit.

    SetConsoleMode(hStdin, fdwSaveOldMode);
 
    return 0; 
}

VOID ErrorExit (LPSTR lpszMessage) 
{ 
    fprintf(stderr, "%s\n", lpszMessage); 

    // Restore input mode on exit.

    SetConsoleMode(hStdin, fdwSaveOldMode);

    ExitProcess(0); 
}

VOID KeyEventProc(KEY_EVENT_RECORD ker)
{
    printf("Key event: ");

    if(ker.bKeyDown)
        printf("key pressed\n");
    else printf("key released\n");
}

VOID MouseEventProc(MOUSE_EVENT_RECORD mer)
{
#ifndef MOUSE_HWHEELED
#define MOUSE_HWHEELED 0x0008
#endif
    printf("Mouse event: ");
    
    switch(mer.dwEventFlags)
    {
        case 0:

            if(mer.dwButtonState == FROM_LEFT_1ST_BUTTON_PRESSED)
            {
                printf("left button press \n");
            }
            else if(mer.dwButtonState == RIGHTMOST_BUTTON_PRESSED)
            {
                printf("right button press \n");
            }
            else
            {
                printf("button press\n");
            }
            break;
        case DOUBLE_CLICK:
            printf("double click\n");
            break;
        case MOUSE_HWHEELED:
            printf("horizontal mouse wheel\n");
            break;
        case MOUSE_MOVED:
            printf("mouse moved\n");
            break;
        case MOUSE_WHEELED:
            printf("vertical mouse wheel\n");
            break;
        default:
            printf("unknown\n");
            break;
    }
}

VOID ResizeEventProc(WINDOW_BUFFER_SIZE_RECORD wbsr)
{
    printf("Resize event\n");
    printf("Console screen buffer is %d columns by %d rows.\n", wbsr.dwSize.X, wbsr.dwSize.Y);
}


 

 

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