modbus_write_and_read_registers(3) ================================== NAME ---- modbus_write_and_read_registers - write and read many registers in a single transaction SYNOPSIS -------- *int modbus_write_and_read_registers(modbus_t *'ctx', int 'write_addr', int 'write_nb', const uint16_t *'src', int 'read_addr', int 'read_nb', const uint16_t *'dest');* DESCRIPTION ----------- The *modbus_write_and_read_registers()* function shall write the content of the _write_nb_ holding registers from the array 'src' to the address _write_addr_ of the remote device then shall read the content of the _read_nb_ holding registers to the address _read_addr_ of the remote device. The result of reading is stored in _dest_ array as word values (16 bits). You must take care to allocate enough memory to store the results in _dest_ (at least _nb_ * sizeof(uint16_t)). The function uses the Modbus function code 0x17 (write/read registers). RETURN VALUE ------------ The function shall return the number of read registers if successful. Otherwise it shall return -1 and set errno. ERRORS ------ *EMBMDATA*:: Too many registers requested, Too many registers to write SEE ALSO -------- linkmb:modbus_read_registers[3] linkmb:modbus_write_register[3] linkmb:modbus_write_registers[3] AUTHORS ------- The libmodbus documentation was written by Stéphane Raimbault