modbus_reply(3)
===============

NAME
----
modbus_reply - send a reponse to the received request


SYNOPSIS
--------
*int modbus_reply(modbus_t *'ctx', const uint8_t *'req', int 'req_length', modbus_mapping_t *'mb_mapping');


DESCRIPTION
-----------
The _modbus_reply()_ function shall send a response to received request. The
request 'req' given in argument is analyzed, a response is then built and sent
by using the information of the modbus context 'ctx'.

If the request indicates to read or write a value the operation will done in the
modbus mapping 'mb_mapping' according to the type of the manipulated data.

If an error occurs, an exception response will be sent.

This function is designed for Modbus server.


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


ERRORS
------
EMBMDATA::
Sending has failed

See also the errors returned by the syscall used to send the response (eg. send
or write).


SEE ALSO
--------
linkmb:modbus_reply_exception[3]
linkmb:libmodbus[7]


AUTHORS
-------
The libmodbus documentation was written by Stéphane Raimbault
<stephane.raimbault@gmail.com>
