LPDEV

Section: Maintenance Commands (8)
Updated: July, 1993
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NAME

lpdev - installs the /dev/lp device

SYNOPSIS

lpdev

DESCRIPTION

lpdev will install /dev/lp , a buffered Centronics device driver. Typically, this command will be put in your mint.cnf file. This device is write-only; you won't be able to read anything from it (it will behave like /dev/null ). It's also very dumb: the bytes written into /dev/lp will be sent without modification to the Centronics port. In fact, the only service offered by /dev/lp is buffering: it should allow you to print without hogging the cpu. To take full advantage of buffering, you should write large blocks of data into /dev/lp , not one byte at a time, in order to reduce system call overhead. The default size of the buffer is 24 kbyte; jobs that print files bigger than that should be put in the background. The ioctl modes recognized by this device are:

FIONREAD, FIONWRITE: return the number of bytes that can be read from (always 0) or written to the device.
TIOCFLUSH: clears the buffer.
F_GETLK, F_SETLK, F_SETLKW: handle file locking on the device. You can only lock the whole device, and only with a write-lock; read-locks are ignored.

DIAGNOSTICS

Error messages are reported on standard output, and lpdev exits with the appropriate return-code (usually EACCDN or ENSMEM).

lpdev: MiNT is not running: self-explanatory
lpdev: device "u:\dev\lp" already installed: self-explanatory
lpdev: Centronics interrupt already in use: The MFP interrupt source #0 is already active, probably because of another spooler.
lpdev: not enough memory: There's no memory left for the circular buffer.
lpdev: unable to install device: MiNT couldn't install the device for another reason that those mentioned above.

AUTHOR

Thierry Bousch (bousch@suntopo.matups.fr)

BUGS

The /dev/lp device can't be opened in exclusive mode; you must open it, then apply a lock on the file descriptor. The file locking functions haven't been tested, so they won't work.

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Time: 08:35:43 GMT, February 14, 2025