canAccept

This routine sets the message acceptance filters on a CAN channel.

flag

Any one of the following values:

Value	Meaning
canFILTER_SET_CODE_STD	Sets the code for standard (11-bit) identifiers.
canFILTER_SET_MASK_STD	Sets the mask for standard (11-bit) identifiers.
canFILTER_SET_CODE_EXT	Sets the code for extended (29-bit) identifiers.
canFILTER_SET_MASK_EXT	Sets the mask for extended (29-bit) identifiers.

canOK (zero) if success
canERR_xxx (negative) if failure.

A binary 1 in a mask means "the corresponding bit in the code is relevant"

A binary 0 in a mask means "the corresponding bit in the code is not relevant"

A relevant binary 1 in a code means "the corresponding bit in the identifier must be 1"

A relevant binary 0 in a code means "the corresponding bit in the identifier must be 0"

In other words, the message is accepted if ((code XOR id) AND mask) == 0.

You can set the extended code and mask only on CAN boards that support extended identifiers.
Not all CAN boards support different masks for standard and extended CAN identifiers.
If you want to remove a filter, call canAccept with the mask set to 0.
On some boards the acceptance filtering is done by the CAN hardware; on other boards (typically those with an embedded CPU,) the acceptance filtering is done by software. canAccept behaves in the same way for all boards, however.
canSetAcceptanceFilter and canAccept both serve the same purpose but the former can set the code and mask in just one call.