Rockwell-automation 1747-PCINT API Software for 1746 I/O Manual de usuario descargar pdf (Pagina 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

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 ... 154 155

Sin comentarios

Rockwell-automation 1747-PCINT API Software for 1746 I/O Manual de usuario Pagina 56