|string||An expression that resolves to a string.|
The CHECKSUM function generates a cyclic redundancy code (also called a checksum) corresponding to string. It returns this checksum as a positive 5-digit integer. A checksum can be used to determine if data has been modified or if it was incompletely transmitted. CHECKSUM uses an 8-bit byte sum mode to calculate the checksum.
CHECKSUM returns the same checksum number for a numeric and the corresponding numeric string. However, numerics are converted to canonical form before checksum processing, whereas numeric strings are not converted to canonical form. Canonical and non-canonical forms of the same number have different checksums.
All string and numeric values, including zero, return a 5-digit checksum. However, if string is a null string a checksum of 0 is returned.
The following examples all return the same checksum:
PRINT CHECKSUM(123.4) PRINT CHECKSUM("123.4") PRINT CHECKSUM(+00123.400)
The following examples do not return the same checksum:
PRINT CHECKSUM(123.400) PRINT CHECKSUM("123.400")