Oc_calculatecrc -2 – Rockwell Automation 1747-PCINT API Software for 1746 I/O User Manual
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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