1MODBUS_REPLY_EXCEPTI(3)        libmodbus Manual        MODBUS_REPLY_EXCEPTI(3)
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NAME

6       modbus_reply_exception - send an exception reponse
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SYNOPSIS

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

13       The modbus_reply_exception() function shall send an exception response
14       based on the exception_code in argument.
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16       The libmodbus provides the following exception codes:
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18       •   MODBUS_EXCEPTION_ILLEGAL_FUNCTION (1)
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20       •   MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS (2)
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22       •   MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE (3)
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24       •   MODBUS_EXCEPTION_SLAVE_OR_SERVER_FAILURE (4)
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26       •   MODBUS_EXCEPTION_ACKNOWLEDGE (5)
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28       •   MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY (6)
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30       •   MODBUS_EXCEPTION_NEGATIVE_ACKNOWLEDGE (7)
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32       •   MODBUS_EXCEPTION_MEMORY_PARITY (8)
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34       •   MODBUS_EXCEPTION_NOT_DEFINED (9)
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36       •   MODBUS_EXCEPTION_GATEWAY_PATH (10)
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38       •   MODBUS_EXCEPTION_GATEWAY_TARGET (11)
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40       The initial request req is required to build a valid response.
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RETURN VALUE

43       The function shall return the length of the response sent if
44       successful. Otherwise it shall return -1 and set errno.
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ERRORS

47       EINVAL
48           The exception code is invalid
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SEE ALSO

51       modbus_reply(3) libmodbus(7)
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AUTHORS

54       The libmodbus documentation was written by Stéphane Raimbault
55       <stephane.raimbault@gmail.com>
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59libmodbus v3.1.6                  01/19/2023           MODBUS_REPLY_EXCEPTI(3)