Rockwell Automation 1747-PCINT API Software for 1746 I/O - Manual (Page 106)

6–52 Library of Routines OC_ReadHostRetentive Data
Publication 1747-6.5.3 June 1998
OC_ReadHostRetentive
Data OC_ReadHostRetentiveData reads the host-retentive-data partition of the scanner.
Syntax:
int OC_ReadHostRetentiveData(HANDLE handle, BYTE *buf, WORD offset, WORD len);
Parameters:
Description:
Data is not read past the end of the host-retentive-data partition.
It is recommended that you verify the integrity of the data stored in the host-retentive-data partition. You
can use the OC_CalculateCRC function to generate a 16-bit CRC.
Important: The jumper for the battery-backup dual-port memory is disabled by
default. You must switch the jumper to enable the battery-backup
feature.
Return Value:
Considerations:
Supported in the DOS API library and the Windows NT API library
Parameter: Description:
handle Must be a valid handle returned from OC_OpenScanner
buf Contains the data that is read
offset
The data is read offset bytes from the beginning of the data partition
If the number of bytes from offset to the end of the partition is smaller
than len , no bytes will be read and ERR_OCPARAM is returned.
len Defines how many bytes to read
Name: Value: Description:
SUCCESS 0 host retentive data was written successfully
ERR_OCACCESS
2
handle does not have access to scanner
ERR_OCINIT 5 scanner has not been initialized, see OC_InitScanner
ERR_OCPARAM 8 parameter contains invalid value