SYNOPSIS

           #include <ieee1284.h>
           cc files... -lieee1284

OVERVIEW

       The  libieee1284  library  is  a  library  for  accessing parallel port
       devices.


       The model presented to the user is fairly abstract: a list of  parallel
       ports  with  arbitrary  names, with functions to access them in various
       ways ranging from bit operations to block data transfer in one  of  the
       IEEE 1284 sanctioned protocols.


       Although the library resides in user space the speed penalty may not be
       as bad as you initially think, since the operating system may well pro-
       vide assistance with block data transfer operations; in fact, the oper-
       ating system may even use hardware assistance to get the job done.  So,
       using libieee1284, ECP transfers using DMA are possible.


       The normal sequence of events will be that the application


       1. calls ieee1284_find_ports to get a list of available ports

       2. then ieee1284_get_deviceid to look for a device on each port that it
          is interested in

       3. and then ieee1284_open to open each port it finds a  device  it  can
          control on.

       4. The  list of ports returned from ieee1284_find_ports can now be dis-
          posed of using ieee1284_free_ports.

       5. Then  when  it  wants  to  control  the   device,   it   will   call
          ieee1284_claim to prevent other drivers from using the port

       6. then perhaps do some data transfers

       7. and  then  ieee1284_release when it is finished that that particular
          command. This claim-control-release sequence will be  repeated  each
          time it wants to tell the device to do something.

       8. Finally  when  the  application  is finished with the device it will
          call ieee1284_close.




       Comments  begin with a '#' character and extend to the end of the line.
       Everything else is  freely-formatted  tokens.  A  non-quoted  (or  dou-
       ble-quoted)  backslash character '\' preserves the literal value of the
       next character, and single and double quotes may be used for preserving
       white-space.  Braces  and equals signs are recognised as tokens, unless
       quoted or escaped.


       The only configuration instruction  that  is  currently  recognised  is
       ``disallow  method  ppdev'',  for preventing the use of the Linux ppdev
       driver.

ENVIRONMENT

       You can enable debugging output from the library by setting  the  envi-
       ronment variable LIBIEEE1284_DEBUG to any value.

FILES

       /etc/ieee1284.conf
              Configuration file.

SEE ALSO

       parport(3),           parport_list(3),          ieee1284_find_ports(3),
       ieee1284_free_ports(3),   ieee1284_get_deviceid(3),   ieee1284_open(3),
       ieee1284_close(3),        ieee1284_claim(3),       ieee1284_release(3),
       ieee1284_data(3),       ieee1284_status(3),        ieee1284_control(3),
       ieee1284_negotiation(3),   ieee1284_ecp_fwd_to_rev(3),  ieee1284_trans-
       fer(3), ieee1284_get_irq_fd(3), ieee1284_set_timeout(3)

AUTHOR

       Tim Waugh <twaugh@redhat.com>.



                                                                LIBIEEE1284(3)