console(4spp) — mips UMIPS RISC/os 5.01



CONSOLE(4spp)       RISC/os Reference Manual        CONSOLE(4spp)



NAME
     console - multiple device system console

SYNOPSIS
     {
          "console",     nulldev, nulldev,
          pconsstrategy, nulldev,     pconsioctl,
          DTTYPECHAR,
          DTFSNONE,     "pseudo console"
     }

DESCRIPTION
     Console is the device name for a pseudo-device that
     represents the currently enabled console devices (see
     enable(1spp)).  The console device allows multiple devices
     to function simultaneously as the system console.  Console
     input is accepted from all enabled devices; console output
     goes to all enabled devices.  The set of console initially
     enabled is controlled by the environment variable $console.
     If the first letter of $console is "a" or "r", both tty(0)
     and tty(1) are enabled; otherwise only tty(0) is enabled.
     The console device is primarily useful to allow remote sys-
     tem debugging.

IOCTLS
     The console device supports the following ioctls:

   ioctl(fd, PIOCENABLE, device)
     Device is a character pointer to a null-terminated string
     giving the name of a device.  That device is added to the
     list of currently enabled console devices.

   ioctl(fd, PIOCDISABLE, device)
     Device is a character pointer to a null-terminated string
     giving the name of a device.  That device is removed from
     the list of currently enabled console devices.

   ioctl(fd, PIOCSHOW, 0)
     Display on console output the list of currently enabled con-
     sole devices.

     Any other ioctl's given to the console device are passed on
     to the currently enabled console devices.

DIAGNOSTICS
     The following diagnostics are issued by the console device:

     can't open %s
          A device specified by a PIOCENABLE or PIOCDISABLE ioctl
          could not be opened

     %s is not a char device



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CONSOLE(4spp)       RISC/os Reference Manual        CONSOLE(4spp)



          A device specified by a PIOCENABLE ioctl is not
          appropriate as a console device

     %s is already enabled
          A device specified by a PIOCENABLE ioctl is currently
          enabled

     %s not enable
          A device specified by a PIOCDISABLE ioctl is not
          currently enabled

     too many consoles enabled
          An attempt has been made to enable more devices via
          PIOCENABLE than are currently supported by the console
          device driver

     enable(1spp), tty(4spp)






































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