Module sysvar 

Sysvar access via direct syscalls.

Provides zero-alloc, zero-deserialization access to Solana sysvars by reading them directly into stack buffers via syscalls, including the epoch schedule sysvar.

Re-exports

pub use crate::arith::saturating_mul_u64;

Structs

Clock

Clock sysvar data, read directly from the runtime.

EpochRewards

EpochRewards sysvar data (SIMD-0118).

EpochSchedule

Epoch schedule sysvar data.

Rent

Rent sysvar data.

SlotHash

One (slot, hash) entry from the SlotHashes sysvar.

StakeHistoryEntry

One epoch’s stake-history entry.

Constants

ACCOUNT_STORAGE_OVERHEAD

Fixed per-account storage overhead charged by the cluster.

CLOCK_ID

Clock sysvar address.

EPOCH_REWARDS_ID

EpochRewards sysvar address (SIMD-0118).

EPOCH_SCHEDULE_ID

Epoch schedule sysvar address.

EPOCH_SCHEDULE_IMAGE_LEN

Length of the EpochSchedule sysvar’s account image.

EXEMPTION_THRESHOLD_YEARS

Years of rent an account must prepay to be rent-exempt.

INSTRUCTIONS_ID

Instructions sysvar address (for instruction introspection).

LAMPORTS_PER_BYTE_YEAR

Lamports charged per byte of account storage per year.

LAST_RESTART_SLOT_ID

LastRestartSlot sysvar address.

RENT_ID

Rent sysvar address.

RENT_IMAGE_LEN

Length of the Rent sysvar’s account image: u64 + f64 + u8.

SLOT_HASHES_ID

SlotHashes sysvar address.

STAKE_HISTORY_ID

StakeHistory sysvar address.

Functions

decode_epoch_schedule

Decode the EpochSchedule account image (epoch_schedule_decodes_canonical_image pins the offsets).

get_clock

Read the Clock sysvar.

get_epoch_rewards

Read the EpochRewards sysvar (SIMD-0118).

get_epoch_schedule

Read the EpochSchedule sysvar.

get_epoch_stake

Get the current-epoch activated stake of the vote account at vote.

get_last_restart_slot

Read the slot of the last cluster restart (hard fork), or 0 if the cluster has never been restarted.

get_rent

Read the Rent sysvar.

get_sysvar_into

Copy dst.len() bytes starting at offset from the sysvar identified by sysvar_id into dst.

get_sysvar_prefix_at

get_sysvar_into that reports a read past the sysvar’s end as Ok(false) instead of an error, so a caller can read an optimistic prefix (a length word plus the first entry) in one syscall and fall back only when the sysvar is shorter than that.

get_total_epoch_stake

Get the cluster-wide total activated stake for the current epoch.

rent_exempt_minimum

Minimum balance for rent exemption assuming the launch-era rent constants (LAMPORTS_PER_BYTE_YEAR, EXEMPTION_THRESHOLD_YEARS, ACCOUNT_STORAGE_OVERHEAD).

scale_by_exemption_threshold

Apply the rent exemption_threshold (given as its IEEE-754 bit pattern) to an integer lamport amount without any floating-point instruction.

slot_hashes_latest

Read the most recent (slot, hash) from the SlotHashes sysvar.

stake_history_latest

Read the most recent stake-history entry.