modbus_set_slave(3) =================== NAME ---- modbus_set_slave - set slave number in the context SYNOPSIS -------- *int modbus_set_slave(modbus_t *'ctx', int 'slave');* DESCRIPTION ----------- The *modbus_set_slave()* function shall set the slave number in the libmodbus context. The behavior depends of network and the role of the device: *RTU*:: Define the slave ID of the remote device to talk in master mode or set the internal slave ID in slave mode. According to the protocol, a Modbus device must only accept message holing its slave number or the special broadcast number. *TCP*:: The slave number is only required in TCP if the message must reach a device on a serial network. The special value `MODBUS_TCP_SLAVE` (0xFF) can be used in TCP mode to restore the default value. The broadcast address is `MODBUS_BROADCAST_ADDRESS`. This special value must be use when you want all Modbus devices of the network receive the request. RETURN VALUE ------------ The function shall return 0 if successful. Otherwise it shall return -1 and set errno to one of the values defined below. ERRORS ------ *EINVAL*:: The slave number is invalid. AUTHORS ------- The libmodbus documentation was written by Stéphane Raimbault