Kvaser Linux CANLIB
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You can send remote requests by passing the canMSG_RTR flag to canWrite(). Received remote frames are reported by canRead et al using the same flag.
Nearly all hardware platforms support detection of error frames. If an error frame arrives, the flag canMSG_ERROR_FRAME is set in the flag argument of canRead(). The identifier is garbage if an error frame is received, but for LAPcan it happens to be 2048 plus the error code from the SJA1000.
Many platforms (for example, LAPcan, Leaf, and USBcan II) support transmission of error frames as well. To send error frames, set the canMSG_ERROR_FRAME flag in the flag argument to canWrite().
These aren't used nowadays. Certain old CAN controllers (Intel 82526) used them to delay frame processing in certain cases.