modbus_reply - send a response to the received request

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

libmodbus v3.1.6                                   12/09/2019                                    MODBUS_REPLY(3)

       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.

EMBMDATA
           Sending has failed

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

       modbus_reply - send a response to the received request

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

modbus_reply_exception(3) libmodbus(7)

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