The OpenNET Project / Index page

[ новости /+++ | форум | теги | ]

Интерактивная система просмотра системных руководств (man-ов)

 ТемаНаборКатегория 
 
 [Cписок руководств | Печать]

vkbd (4)
  • vkbd (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • >> vkbd (4) ( FreeBSD man: Специальные файлы /dev/* )

  • BSD mandoc
     

    NAME

    vkbd
    
     - the virtual AT keyboard interface
    
     
    

    SYNOPSIS

    device vkbd  

    DESCRIPTION

    The interface is a software loopback mechanism that can be loosely described as the virtual AT keyboard analog of the pty(4), that is, does for virtual AT keyboards what the pty(4) driver does for terminals.

    The driver, like the pty(4) driver, provides two interfaces: a keyboard interface like the usual facility it is simulating (a virtual AT keyboard in the case of , or a terminal for pty(4)), and a character-special device ``control'' interface.

    The virtual AT keyboards are named vkbd0 , vkbd1 etc., one for each control device that has been opened.

    The interface permits opens on the special control device /dev/vkbdctl When this device is opened, will return a handle for the lowest unused vkbdctl device (use devname(3) to determine which).

    Each virtual AT keyboard supports the usual keyboard interface ioctl(2)Nss, and thus can be used with kbdcontrol(1) like any other keyboard. The control device supports exactly the same ioctl(2)Nss as the virtual AT keyboard device. Writing AT scan codes to the control device generates an input on the virtual AT keyboard, as if the (non-existent) hardware had just received it.

    The virtual AT keyboard control device, normally /dev/vkbdctl Aq N is exclusive-open (it cannot be opened if it is already open) and is restricted to the super-user. A read(2) call will return the virtual AT keyboard status structure (defined in In dev/vkbd/vkbd_var.h ) if one is available; if not, it will either block until one is or return Er EWOULDBLOCK , depending on whether non-blocking I/O has been enabled.

    A write(2) call passes AT scan codes to be ``received'' from the virtual AT keyboard. Each AT scan code must be passed as Vt unsigned int . Although AT scan codes must be passes as Vt unsigned int Ns s , the size of the buffer passed to write(2) still should be in bytes, i.e.,

    static unsigned int     codes[] =
    {
    /*      Make    Break */
            0x1e,   0x9e
    };
    
    int
    main(void)
    {
            int     fd, len;
    
            fd = open("/dev/vkbdctl0", O_RDWR);
            if (fd < 0)
                    err(1, "open");
    
            /* Note sizeof(codes) - not 2! */
            len = write(fd, codes, sizeof(codes));
            if (len < 0)
                    err(1, "write");
    
            close(fd);
    
            return (0);
    }
    

    Write will block if there is not enough space in the input queue.

    The control device also supports select(2) for read and write.

    On the last close of the control device, the virtual AT keyboard is removed. All queued scan codes are thrown away.  

    SEE ALSO

    kbdcontrol(1), atkbdc(4), psm(4), syscons(4)  

    CAVEATS

    The interface is a software loopback mechanism, and, thus ddb(4) will not work with it. Current implementation of the syscons(4) driver can accept input from only one keyboard, even if it is virtual. Thus it is not possible to have both wired and virtual keyboard to be active at the same time. It is, however, in principal possible to obtain AT scan codes from the different sources and write them into the same virtual keyboard. The virtual keyboard state synchronization is the user's responsibility.  

    HISTORY

    The module was implemented in Fx 6.0 .  

    AUTHORS

    An Maksim Yevmenkin Aq [email protected]


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    SEE ALSO
    CAVEATS
    HISTORY
    AUTHORS


    Поиск по тексту MAN-ов: 




    Партнёры:
    PostgresPro
    Inferno Solutions
    Hosting by Hoster.ru
    Хостинг:

    Закладки на сайте
    Проследить за страницей
    Created 1996-2024 by Maxim Chirkov
    Добавить, Поддержать, Вебмастеру