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MODBUS_REPLY_EXCEPTI(3) Libmodbus Manual MODBUS_REPLY_EXCEPTI(3)

NAME

modbus_reply_exception - send an exception reponse

SYNOPSIS

*int modbus_reply_exception(modbus_t * ctx, const uint8_t *req, unsigned int exception_code);

DESCRIPTION

The modbus_reply_exception() function shall send an exception response based on the exception_code in argument.
The libmodbus provides the following exception codes:
•MODBUS_EXCEPTION_ILLEGAL_FUNCTION (1)
•MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS (2)
•MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE (3)
•MODBUS_EXCEPTION_SLAVE_OR_SERVER_FAILURE (4)
•MODBUS_EXCEPTION_ACKNOWLEDGE (5)
•MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY (6)
•MODBUS_EXCEPTION_NEGATIVE_ACKNOWLEDGE (7)
•MODBUS_EXCEPTION_MEMORY_PARITY (8)
•MODBUS_EXCEPTION_NOT_DEFINED (9)
•MODBUS_EXCEPTION_GATEWAY_PATH (10)
•MODBUS_EXCEPTION_GATEWAY_TARGET (11)
The initial request req is required to build a valid response.

RETURN VALUE

The modbus_reply_exception() function shall return the length of the response sent if successful. Otherwise it shall return -1 and set errno.

ERRORS

EINVAL
The exception code is invalid

SEE ALSO

modbus_reply(3) libmodbus(7)

AUTHORS

The libmodbus documentation was written by Stéphane Raimbault < stephane.raimbault@gmail.com[1]>

NOTES

1.
stephane.raimbault@gmail.com
mailto:stephane.raimbault@gmail.com
10/18/2014 libmodbus 3.0.6