Struct Sysvar

pub struct Sysvar<'info, T>
where
    T: Sysvar,
{ /* private fields */ }

Type validating that the account is a sysvar and deserializing it.

If possible, sysvars should not be used via accounts but by using the get function on the desired sysvar. This is because using get does not run the risk of Anchor having a bug in its Sysvar type and using get also decreases tx size, making space for other accounts that cannot be requested via syscall.

Example

// OK - via account in the account validation struct
#[derive(Accounts)]
pub struct Example<'info> {
    pub clock: Sysvar<'info, Clock>
}
// BETTER - via syscall in the instruction function
fn better(ctx: Context<Better>) -> Result<()> {
    let clock = Clock::get()?;
}

Implementations

impl<'info, T> Sysvar<'info, T>

where T: Sysvar,

pub fn from_account_info( acc_info: &'info AccountInfo<'info>, ) -> Result<Sysvar<'info, T>, Error>

Trait Implementations

impl<'info, B, T> Accounts<'info, B> for Sysvar<'info, T>

where T: Sysvar,

fn try_accounts( _program_id: &Pubkey, accounts: &mut &'info [AccountInfo<'info>], _ix_data: &[u8], _bumps: &mut B, _reallocs: &mut BTreeSet<Pubkey>, ) -> Result<Sysvar<'info, T>, Error>

Returns the validated accounts struct. What constitutes “valid” is program dependent. However, users of these types should never have to worry about account substitution attacks. For example, if a program expects a Mint account from the SPL token program in a particular field, then it should be impossible for this method to return Ok if any other account type is given–from the SPL token program or elsewhere.

impl<'info, T> AccountsExit<'info> for Sysvar<'info, T>

where T: Sysvar,

fn exit(&self, _program_id: &Pubkey) -> Result<(), Error>

program_id is the currently executing program.

impl<'info, T> AsRef<AccountInfo<'info>> for Sysvar<'info, T>

where T: Sysvar,

fn as_ref(&self) -> &AccountInfo<'info>

Converts this type into a shared reference of the (usually inferred) input type.

impl<T> Clone for Sysvar<'_, T>

where T: Sysvar,

fn clone(&self) -> Sysvar<'_, T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Sysvar<'_, T>

where T: Sysvar + Debug,

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

Formats the value using the given formatter.

impl<T> Deref for Sysvar<'_, T>

where T: Sysvar,

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &<Sysvar<'_, T> as Deref>::Target

Dereferences the value.

impl<T> DerefMut for Sysvar<'_, T>

where T: Sysvar,

fn deref_mut(&mut self) -> &mut <Sysvar<'_, T> as Deref>::Target

Mutably dereferences the value.

impl<T> Key for Sysvar<'_, T>

where T: Sysvar,

fn key(&self) -> Pubkey

impl<'info, T> ToAccountInfos<'info> for Sysvar<'info, T>

where T: Sysvar,

fn to_account_infos(&self) -> Vec<AccountInfo<'info>>

impl<T> ToAccountMetas for Sysvar<'_, T>

where T: Sysvar,

fn to_account_metas(&self, _is_signer: Option<bool>) -> Vec<AccountMeta>

is_signer is given as an optional override for the signer meta field. This covers the edge case when a program-derived-address needs to relay a transaction from a client to another program but sign the transaction before the relay. The client cannot mark the field as a signer, and so we have to override the is_signer meta field given by the client.