SCFeederGetFlags(3)

NAME
     SCFeederGetFlags, SCFeederSetFlags, SCFeederAdvance, SCFeederReady -
     scanner document feeder functions

SYNOPSIS
     #include <stdio.h>
     #include <scanner.h>

     int SCFeederGetFlags(SCANNER *s, SCFEEDERFLAGS *flags);

     int SCFeederSetFlags(SCANNER *s, SCFEEDERFLAGS flags);

     int SCFeederAdvance(SCANNER *s);

     int SCFeederReady(SCANNER *s);

DESCRIPTION
     SCFeederGetFlags gets flags that describe a scanner's document feeding
     capabilities.  s specifies a connection to a scanner driver obtained by a
     call to SCOpen(3), SCOpenFile(3), or SCOpenScreen(3).

     SCFEEDERFLAGS and the values it can take on are defined in <scanner.h> as
     follows:

          typedef unsigned int SCFEEDERFLAGS;

          #define SC_HASFEEDER 1
          #define SC_AUTOFEED  2
          #define SC_PROGFEED  4


     The meanings of the flags are as follows:

     SC_HASFEEDER: this flag is set if there is a document feeder attached to
     the scanner.

     SC_AUTOFEED: this flag is set if the feeder can operate such that each
     call to SCScan(3) causes the next document to be loaded.

     SC_PROGFEED: this flag is set if the feeder can operate such that
     SCScan(3) can be called multiple times per document, with a call to
     SCFeederAdvance being necessary to load the next document.

     SCFeederSetFlags should be called before calling SCScan(3) for scanners
     for which SCFeederGetFlags yields both SC_AUTOFEED and SC_PROGFEED set.

     After calling

          SCFeederSetFlags(s, SC_AUTOFEED);


     the feeder will advance to the next document after every call to SCScan.
     After calling

          SCFeederSetFlags(s, SC_PROGFEED);


     a call to SCFeederAdvance after each scan is necessary to advance to the
     next document.

     SCFeederAdvance advances the feeder to the next document.  This call is
     only valid if the scanner supports SC_PROGFEED mode.  In addition, for
     scanners that support both SC_AUTOFEED and SC_PROGFEED mode,

          SCFeederSetFlags(s, SC_PROGFEED);


     must have been called previously.

     Use SCFeederReady to check if the feeder is ready for feeding.

RETURN VALUE
     SCFeederGetFlags, SCFeederSetFlags, and SCFeederAdvance return 0 if
     successful or -1 if an error occurs.

     SCFeederReady returns 0 if the feeder is ready, and -1 with SCerrno set
     to SCFEEDEREMPTY if the feeder is not ready.  If any other error
     conditions exist, SCerrno will be set appropriately.

EXECUTION ERROR CODES
     These functions can all fail due to a communications error with the
     scanner driver, in which case SCerrno will be set as follows.

     SCECOMM                  Error communicating with scanner driver

     Additionally, SCFeederSetFlags, SCFeederAdvance, and SCFeederReady will
     fail under the following circumstances.  circumstances.

     SCENOFEEDER              No feeder

     SCEAUTOONLY              Feeder only supports automatic usage

     SCEFEEDEREMPTY           Feeder empty

     SCEFEEDERJAMMED          Feeder jammed

     SCEFEEDERERR             Feeder error
SEE ALSO
     libscan(3), SCOpen(3), SCScan(3), SCScanFD(3).