Enum Function 

pub enum Function {
    ReadCoils {
        starting_address: u16,
        quantity: u16,
    },
    ReadDiscreteInputs {
        starting_address: u16,
        quantity: u16,
    },
    ReadHoldingRegisters {
        starting_address: u16,
        quantity: u16,
    },
    ReadInputRegisters {
        starting_address: u16,
        quantity: u16,
    },
    WriteSingleCoil {
        address: u16,
        value: bool,
    },
    WriteSingleRegister {
        address: u16,
        value: u16,
    },
    WriteMultipleCoils {
        starting_address: u16,
        value: Box<[bool]>,
    },
    WriteMultipleRegisters {
        starting_address: u16,
        value: Box<[u16]>,
    },
}

Function

Represents a Modbus RTU function request along with the data required to encode it into a protocol-compliant frame.

Variants

ReadCoils

Read Coils (0x01)

Fields

starting_address: u16

quantity: u16

ReadDiscreteInputs

Read Discrete Inputs (0x02)

Fields

starting_address: u16

quantity: u16

ReadHoldingRegisters

Read Holding Registers (0x03)

Fields

starting_address: u16

quantity: u16

ReadInputRegisters

Read Input Registers (0x04)

Fields

starting_address: u16

quantity: u16

WriteSingleCoil

Write Single Coil (0x05)

Fields

address: u16

value: bool

WriteSingleRegister

Write Single Register (0x06)

Fields

address: u16

value: u16

WriteMultipleCoils

Write Multiple Coils (0x0F)

Fields

starting_address: u16

value: Box<[bool]>

WriteMultipleRegisters

Write Multiple Registers (0x10)

Fields

starting_address: u16

value: Box<[u16]>

Implementations

impl Function

pub const fn kind(&self) -> FunctionKind

Returns the [FunctionKind] associated with this request.

---

Examples

use modbus_rtu::{Function, FunctionKind};

let function = Function::ReadCoils { starting_address: 0, quantity: 2 };
assert_eq!(function.kind(), FunctionKind::ReadCoils);

pub const fn as_code(&self) -> u8

Returns the Modbus RTU function code for this request.

---

Examples

use modbus_rtu::Function;

let function = Function::WriteSingleRegister { address: 0x10, value: 0x1234 };
assert_eq!(function.as_code(), 0x06);

pub const fn expected_len(&self) -> usize

Returns the minimum expected response length for this function.

This helps callers pre-allocate receive buffers before the Modbus frame arrives.

---

Examples

use modbus_rtu::Function;

let func = Function::ReadHoldingRegisters { starting_address: 0, quantity: 2 };
assert_eq!(func.expected_len(), 5 + (2 * 2));

Trait Implementations

impl Clone for Function

fn clone(&self) -> Function

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Function

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Function

fn eq(&self, other: &Function) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Function

impl StructuralPartialEq for Function