Public Function CRC32File( _ ByVal vFileName As Variant _ , Optional ByVal vStartCRC As Variant _ ) As Variant
Assuming CRC32String("ABCD") = -619241307 StringToFile("ABCD", "C:\Test.Out") = True for example CRC32File("C:\Test.Out") = -619241307See also:
CRC32String Function Checksum32File Function CRC32FileSample SubroutinevFileName: Name of the file for which the CRC will be calculated. Function returns Null if vFileName is Null or cannot be fixed-up to a string. Function returns Null if there is any type of error, such as when the file does not exist.
vStartCRC: The starting CRC value. vStartCRC defaults to &HFFFFFFFF (2^32 - 1 unsigned long; -1 signed long) if it is missing or Null or cannot be fixed up to a number. The default CRC value of &HFFFFFFFF should be used in most cases where the CRC of a single string is to be calculated. This argument is provided for those cases where the CRC of multiple FILES are to be calculated one file at a time.
Note: This function returns a Long integer value which really represents an unsigned long value. The most-significant-bit of the return value really represents the most significant bit of an unsigned value; it does not represent the sign bit of a signed value. For example, negative return values represent the values within the range from 2^31 through 2^32-1.
v1.1 BugBix: Corrected a bug in this function that might have caused it to not work in v1.0. For some reason, VB 4.0 was truncating all of the Long hex Constants that were required by this function.
Tip: We suggest using Long decimal Constants (like -1&) instead of Long hex Constants (like &HFFFFFFFF) wherever possible.
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