account_delete

Overview

The account_delete syscall marks an account as deleted by setting the DELETED flag. The account must have zero balance and be writable by the current program.

Syscall Code

Code: 0x06 (TN_SYSCALL_CODE_ACCOUNT_DELETE)

C SDK Function

ulong tsys_account_delete(ulong account_idx);

Arguments

account_idx · ulong · required

Index of the account to delete. Must be writable by the current program and have zero balance.

Return Value

Returns a syscall result code:

Success · ulong

• TN_VM_SYSCALL_SUCCESS (0) - Account marked as deleted successfully

Error Codes · ulong

• TN_VM_ERR_SYSCALL_INVALID_ACCOUNT_INDEX (-8) - Account index out of bounds
• TN_VM_ERR_SYSCALL_ACCOUNT_DOES_NOT_EXIST (-9) - Account does not exist
• TN_VM_ERR_SYSCALL_ACCOUNT_NOT_WRITABLE (-10) - Account not writable by current program
• TN_VM_ERR_SYSCALL_INVALID_ACCOUNT (-27) - Account has non-zero balance or non-zero nonce
• TN_VM_ERR_SYSCALL_STATE_BYTES_REMOVED_OVERFLOW (-48) - State bytes counter overflow during deactivation

Resource Consumption

Compute Units

• Base cost: TN_VM_SYSCALL_BASE_COST (512 units)
• Additional cost: None
• Total cost: Fixed at 512 units

Memory Pages

• Page usage: No immediate page deallocation (pages freed during garbage collection)
• Metadata impact: May trigger metadata page allocation if not already writable
• Future cleanup: Pages will be reclaimed after transaction completion

State Counter Impact

• GDSC (Global Deactivated State Counter): Incremented by TSDK_ACCOUNT_META_FOOTPRINT + account_data_sz bytes
• Purpose: Tracks deactivated state for the account deletion in the global state counter
• Overflow protection: Returns TN_VM_ERR_SYSCALL_STATE_BYTES_REMOVED_OVERFLOW if counter would overflow

Side Effects

• Account state: Sets the DELETED flag on the account
• Metadata: Makes account metadata writable if not already
• Data retention: Account data and metadata remain accessible until garbage collection

Usage Notes

• Account must have exactly zero balance before deletion
• Only the account owner (program) can delete the account
• Deleted accounts can be recreated with account_create (removes DELETED flag)
• Account data remains accessible during the transaction even after deletion
• The account becomes eligible for garbage collection after transaction completion

Deletion vs Compression

Operation	Purpose	Requirements	Effect
Delete	Remove account	Zero balance, ownership	Sets DELETED flag
Compress	Archive account	State proof	Sets COMPRESSED flag

Example

#include <thru-sdk/c/tn_sdk_syscall.h>

// Delete an account (must have zero balance)
ulong account_idx = 2;

// First ensure the account has zero balance
// (transfer out any remaining balance first)

ulong result = tsys_account_delete(account_idx);

if (result == TN_VM_SYSCALL_SUCCESS) {
    // Account marked as deleted
    // Will be garbage collected after transaction
    // Can still access data during this transaction
    // Can be recreated with account_create
}