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:
o MODBUS_EXCEPTION_ILLEGAL_FUNCTION (1)
o MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS (2)
o MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE (3)
o MODBUS_EXCEPTION_SLAVE_OR_SERVER_FAILURE (4)
o MODBUS_EXCEPTION_ACKNOWLEDGE (5)
o MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY (6)
o MODBUS_EXCEPTION_NEGATIVE_ACKNOWLEDGE (7)
o MODBUS_EXCEPTION_MEMORY_PARITY (8)
o MODBUS_EXCEPTION_NOT_DEFINED (9)
o MODBUS_EXCEPTION_GATEWAY_PATH (10)
o 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 Stephane Raimbault <stephane.raimbault@gmail.com[1]>
NOTES
1. stephane.raimbault@gmail.com
mailto:stephane.raimbault@gmail.com
libmodbus 3.0.3 05/26/2012 MODBUS_REPLY_EXCEPTI(3)