SCGetStatus(3)

NAME
     SCGetStatus, SCGetStatusFD - Get status information about a scanner

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

     int SCGetStatus(SCANNER *s, SCSTATUS *st);

     int SCGetStatusFD(SCANNER *s);

DESCRIPTION
     SCGetStatus gets status information from a scanner driver.

     s specifies a connection to a scanner driver obtained from a call to
     SCOpen(3), SCOpenFile(3), or SCOpenScreen(3).

     SCSTATUS is defined in <scanner.h> as follows:

          enum scstate { SC_READY, SC_SCANNING, SC_ERROR };

          typdef struct tag_scstatus {
              enum scstate state;
              int errno;
              long curline;
              int pass;
          } SCSTATUS;


     state is SC_READY if the scanner is idle, waiting for commands.  If a
     scan is in progress, state is SC_SCANNING, and if an error has occurred
     state is SC_ERROR and errno will be set to indicate the cause of the
     error condition.  errno takes on the same values that the global variable
     SCerrno does.

     If state is SC_SCANNING, curline indicates the number of the last scan
     line which was fully processed by the scanner driver, and pass indicates
     which pass is currently being processed.  During the first scanning pass
     of a multiple pass scan, pass will be 0, during the second pass will be
     1, etc.

     SCGetStatusFD returns a file descriptor which can be passed to the
     select(2) system call.  When select(2) indicates that the file descriptor
     is ready for reading, the scanner driver has updated the scanning status.
     Retrieve the status by calling SCGetStatus; do NOT pass the file
     descriptor returned from SCGetStatusFD to any other system call.

     SCGetStatusFD provides a mechanism whereby it is not necessary for an
     application to periodically call SCGetStatus in a timer loop to detect
     changes in scanner status.
RETURN VALUE
     SCGetStatus returns 0 if successful, or -1 if an error occurs.

     SCGetStatusFD returns a file descriptor if successful, or -1 if an error
     occurs.

     If either function returns -1, The global variable SCerrno will be set to
     indicate the reason for the error.

EXECUTION ERROR CODES
     SCGetStatus and SCGetStatusFD will fail under the following
     circumstances.

     SCECOMM                  Error communicating with scanner driver

     SCEDRVMSG                Driver specific error.  SCErrorString(3) will
                              return a custom message supplied by the scanner
                              driver

SEE ALSO
     libscan(3), SCOpen(3), SCScan(3), SCScanFD(3).