Rockwell Automation 1747-PCINT API Software for 1746 I/O - Manual (Page 56)

6–2 Library of Routines OC_CalculateCRC
Publication 1747-6.5.3 June 1998
OC_CalculateCRC OC_CalculateCRC calculates a 16-bit CRC.
Syntax:
void OC_CalculateCRC(BYTE *bufPtr, WORD bLen, WORD *Crc);
Parameters:
Description:
This function is useful for verifying data integrity. For example, a CRC might be appended to data stored
in the host retentive data partition. When the data is later retrieved, a new CRC can be calculated and
compared to the old CRC to ensure the data is valid.
Return Value:
none
Considerations:
Supported in the DOS API library and the Windows NT API library
Example:
BYTE buffer[100];
WORD buffer_crc;
int retcode;
retcode = OC_CalculateCRC( buffer, 100, &buffer_crc );
Parameter: Description:
bufPtr Points to the buffer that contains the bytes for the CRC calculation
bLen Number of bytes for which to calculate the CRC
Crc A word that returns the calculated CRC