Module rwLib.a

This module send command to an EPSON printer. It is delivered as
object file.
The printer supplier dont like that control sequence will be made
public, and I have signed a NDA (Non Disclosure Agreement).


Actually the following is implemented:

InkQuantity:
   send the control sequence for reading back of the remainning
   ink quantity.
   
CleanHead:
   Send the control command for cleaning of the head.
   
PrintPattern:
   Send a command to the printer which alow to print a nozzle pattern.
   
GetId:
   Send the request for identification of the attached printer.

The module contain only one public function. The function
int SendCmd(int hd, char *command, ssize_t (Write(int, const void *, size_t)))
must be called with the following arguments:

hd is a file handle returned from open("/dev/lp0", "rw");

command is one of the following:

- "InkQuantity"
- "CleanHead"
- "PrintPattern"
- "GetId"

Write is a function pointer which wil be used to send the commands
to the printer. Normally this will be the system call write().
Your own application may be compiled under different OS release
and it is possible that integrating of a system call directly in
the module cause problems.

The function SndCmd() return 0 if all is OK and 1 in case of failure.
