CONSOLE(4spp)
NAME
console − multiple device system console
SYNOPSIS
{
"console",_nulldev,_nulldev,
_pconsstrategy, _nulldev,_pconsioctl,
DTTYPE_CHAR,
DTFS_NONE,"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 simultaneous 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 system debugging.
IOCTLS
The console device supports the following ioctl’s:
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 console 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
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