SCGetStatus(3) Impressario 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);
DESCRIPTIONSCGetStatus 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.
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SCGetStatus(3) Impressario SCGetStatus(3)RETURN VALUESCGetStatus 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 CODESSCGetStatus 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 ALSOlibscan(3), SCOpen(3), SCScan(3), SCScanFD(3).
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