Documentation Index
Fetch the complete documentation index at: https://docs.thru.org/llms.txt
Use this file to discover all available pages before exploring further.
Use this page when you need to inspect the current transaction, understand account indexing, or safely read account and block metadata.
Transaction root
Most in-program reads start from:
tsdk_txn_t const * txn = tsdk_get_txn( );
tn_sdk_txn.h expose the fields you usually care about.
Transaction helper reference
| Helper | What it returns |
|---|
tsdk_txn_get_instr_data(txn) | Pointer to instruction bytes. |
tsdk_txn_get_instr_data_sz(txn) | Instruction byte length. |
tsdk_txn_get_msg(txn) | Message portion of the transaction. |
tsdk_txn_get_msg_sz(txn_sz) | Message size excluding trailing signature. |
tsdk_txn_get_fee_payer_signature(txn, txn_sz) | Pointer to the trailing fee-payer signature. |
tsdk_txn_get_fee(txn) | Requested fee. |
tsdk_txn_get_nonce(txn) | Transaction nonce. |
tsdk_txn_get_start_slot(txn) | First valid slot. |
tsdk_txn_get_expiry_slot(txn) | Last valid slot derived from start_slot + expiry_after. |
tsdk_txn_get_chain_id(txn) | Chain identifier. |
tsdk_txn_get_requested_compute_units(txn) | Requested compute units. |
tsdk_txn_get_requested_memory_units(txn) | Requested memory units. |
tsdk_txn_has_fee_payer_state_proof(txn) | Whether a fee-payer proof is present. |
tsdk_txn_get_acct_addrs(txn) | Pointer to fee payer, program, and remaining account pubkeys. |
tsdk_txn_account_cnt(txn) | Total account count exposed to the transaction. |
tsdk_txn_readwrite_account_cnt(txn) | Read-write account count from the header. |
tsdk_txn_readonly_account_cnt(txn) | Read-only account count from the header. |
tsdk_txn_is_account_idx_writable(txn, idx) | Whether the account index is writable in the transaction. |
tsdk_txn_get_msg_sz(txn_sz) is the one helper in this group that only needs the total transaction size. It computes message size = txn_sz - TN_TXN_SIGNATURE_SZ, so it does not need the transaction pointer.
Account indexing
The public helpers assume transaction account indexing like this:
| Index range | Meaning |
|---|
0 | Fee payer |
1 | Current program account |
2+ | User-supplied read-write and read-only accounts |
tsdk_is_account_idx_valid(idx) before indexing transaction-linked account data.
tsdk_get_account_meta(account_idx) returns a tsdk_account_meta_t const * with:
| Field | Meaning |
|---|
version | Whether the metadata is present and versioned. |
flags | Bitfield of account properties (see flag constants below). |
data_sz | Account data size. |
seq | Sequence number. |
owner | Owner program pubkey. |
balance | Native token balance. |
nonce | Account nonce. |
tsdk_account_exists(account_idx) is a convenient existence check built on top of metadata version.
Account flag constants
The flags field on tsdk_account_meta_t is a bitfield. Test individual flags with bitwise AND:
| Constant | Value | Meaning |
|---|
TSDK_ACCOUNT_FLAG_PROGRAM | 0x01 | Account contains executable program code. |
TSDK_ACCOUNT_FLAG_PRIVILEGED | 0x02 | Account has privileged system-level access. |
TSDK_ACCOUNT_FLAG_UNCOMPRESSABLE | 0x04 | Account cannot be compressed. |
TSDK_ACCOUNT_FLAG_EPHEMERAL | 0x08 | Account exists only for the current transaction. |
TSDK_ACCOUNT_FLAG_DELETED | 0x10 | Account has been deleted. |
TSDK_ACCOUNT_FLAG_NEW | 0x20 | Account has never existed before this transaction. |
TSDK_ACCOUNT_FLAG_COMPRESSED | 0x40 | Account state is compressed (removed from active ledger). |
tsdk_account_meta_t const * meta = tsdk_get_account_meta( account_idx );
if( meta->flags & TSDK_ACCOUNT_FLAG_PROGRAM ) {
/* account is a program */
}
tsys_account_set_flags(account_idx, flags) to modify flags on accounts owned by the current program.
Account data pointers
tsdk_get_account_data_ptr(account_idx) returns a raw pointer into the VM account-data segment.
Typical pattern:
ushort account_idx = 2U;
if( !tsdk_is_account_idx_valid( account_idx ) ) tsdk_revert( 1UL );
if( !tsdk_account_exists( account_idx ) ) tsdk_revert( 2UL );
void * data = tsdk_get_account_data_ptr( account_idx );
tsdk_account_meta_t const * meta = tsdk_get_account_meta( account_idx );
Block context
| Helper | Use it for |
|---|
tsdk_get_current_block_ctx() | Current slot, block time, block price, state root, current block hash, and block producer. |
tsdk_get_past_block_ctx(blocks_in_past) | Access a previous block context spaced by TSDK_BLOCK_CTX_VM_SPACING. |
tsdk_block_ctx_t.
Shadow stack and current program identity
| Helper | Use it for |
|---|
tsdk_get_shadow_stack() | Read call depth and CPI frame information. |
tsdk_get_current_program_acc_idx() | Resolve the current program’s transaction account index. |
tsdk_get_current_program_acc_addr() | Resolve the current program’s pubkey. |
tsdk_is_program_reentrant() | Detect whether the current program already appears lower in the call chain. |
tsdk_is_account_authorized_by_idx(...) | Check effective authorization by account index, including CPI auth/deauth state. |
tsdk_is_account_authorized_by_pubkey(...) | Check effective authorization by pubkey. |
tsdk_is_account_owned_by_current_program(...) | Check whether the current program owns an account. |
Notes
- Do not assume every account index is valid just because the instruction payload contains it.
- Metadata and data pointers come from VM-managed memory; treat them as borrowed pointers, not owned allocations.
- Writable status comes from transaction context and syscalls, not from the presence of a data pointer alone.
