[−][src]Crate frame_system

System Module

The System module provides low-level access to core types and cross-cutting utilities. It acts as the base layer for other SRML modules to interact with the Substrate framework components.

system::Trait

Overview

The System module defines the core data types used in a Substrate runtime. It also provides several utility functions (see Module) for other runtime modules.

In addition, it manages the storage items for extrinsics data, indexes, event records, and digest items, among other things that support the execution of the current block.

It also handles low-level tasks like depositing logs, basic set up and take down of temporary storage entries, and access to previous block hashes.

CheckWeight: Checks the weight and length of the block and ensure that it does not exceed the limits.
CheckNonce: Checks the nonce of the transaction. Contains a single payload of type T::Index.
CheckEra: Checks the era of the transaction. Contains a single payload of type Era.
CheckGenesis: Checks the provided genesis hash of the transaction. Must be a part of the signed payload of the transaction.
CheckVersion: Checks that the runtime version is the same as the one encoded in the transaction.

Lookup the runtime aggregator file (e.g. node/runtime) to see the full list of signed extensions included in a chain.

use frame_support::{decl_module, dispatch};
use frame_system::{self as system, ensure_signed};

pub trait Trait: system::Trait {}

decl_module! {
	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
		pub fn system_module_example(origin) -> dispatch::DispatchResult {
			let _sender = ensure_signed(origin)?;
			let _extrinsic_count = <system::Module<T>>::extrinsic_count();
			let _parent_hash = <system::Module<T>>::parent_hash();
			Ok(())
		}
	}
}

Modules

offchain

Module helpers for offchain calls.

Structs

AccountNonce	Extrinsics nonce for accounts.
BlockHash	Map of block numbers to block hashes.
ChainContext
CheckEra	Check for transaction mortality.
CheckGenesis	Nonce check and increment to give replay protection for transactions.
CheckNonce	Nonce check and increment to give replay protection for transactions.
CheckVersion	Ensure the runtime version registered in the transaction is the same as at present.
CheckWeight	resource limit check.
EnsureNever
EnsureNone
EnsureRoot
EnsureSigned
EnsureSignedBy
EventRecord	Record of an event happening.
GenesisConfig
Module

Enums

Call	Dispatchable calls.
Error	Error for the System module
Event	Events for this module.
Phase	A phase of a block's execution.
RawOrigin	Origin for the System module.

Traits

IsDeadAccount	Determiner to say whether a given account is unused.
OnNewAccount	Handler for when a new account has been created.
Trait

Functions

ensure_none	Ensure that the origin `o` represents an unsigned extrinsic. Returns `Ok` or an `Err` otherwise.
ensure_root	Ensure that the origin `o` represents the root. Returns `Ok` or an `Err` otherwise.
ensure_signed	Ensure that the origin `o` represents a signed extrinsic (i.e. transaction). Returns `Ok` with the account that signed the extrinsic or an `Err` otherwise.
extrinsics_data_root	Compute the trie root of a list of extrinsics.
extrinsics_root	Compute the trie root of a list of extrinsics.

Type Definitions

DigestItemOf
DigestOf
Key
KeyValue
Origin	Exposed trait-generic origin type.

[−][src]Crate frame_system

System Module

Overview

Interface

Dispatchable Functions

Public Functions

Signed Extensions

Usage