/**    *  Gets the block number used for TAPOS on the currently executing transaction.    *    *  @ingroup transaction    *  @return block number used for TAPOS on the currently executing transaction    *  Example:    *  @code    *  int tbn = tapos_block_num();    *  @endcode    */   inline int tapos_block_num() {      return internal_use_do_not_use::tapos_block_num();   }

#include <eosio/transaction.hpp>#include <eosio/eosio.hpp>uint16_t current_block_num = tapos_block_num(); // 获取用于当前执行交易所在的区块号

/**    *  Gets the block prefix used for TAPOS on the currently executing transaction.    *    *  @ingroup transaction    *  @return block prefix used for TAPOS on the currently executing transaction    *  Example:    *  @code    *  int tbp = tapos_block_prefix();    *  @endcode    */   inline int tapos_block_prefix() {      return internal_use_do_not_use::tapos_block_prefix();   }

#include <eosio/transaction.hpp>#include <eosio/eosio.hpp>uint32_t current_block_prefix = tapos_block_prefix(); // 获取用于当前执行交易所在的区块哈希前缀

Transaction as Proof of Stake (TaPoS)The EOS.IO software requires every transaction to include part of the hash of a recent block header. This hash serves two purposes:1. prevents a replay of a transaction on forks that do not include the referenced block.//防止在不包含引用区块的分叉上重放交易。2. signals the network that a particular user and their stake are on a specific fork.//向网络发出信号，表明特定用户及其权益位于哪条特定分叉上。Over time all users end up directly confirming the blockchain which makes it difficult to forge counterfeit chains as the counterfeit would not be able to migrate transactions from the legitimate chain.

// eosio.cdt/1.8.1/include/eosiolib/contracts/eosio/transaction.hppclass transaction_header {   public:      /**       * Construct a new transaction_header with an expiration of now + 60 seconds.       *       * @brief Construct a new transaction_header object initialising the transaction header expiration to now + 60 seconds       */      transaction_header( time_point_sec exp = time_point_sec(current_time_point()) + 60)         :expiration(exp)      {}
      time_point_sec  expiration;      /// the time at which a transaction expires      uint16_t        ref_block_num;       /// specifies a block num in the last 2^16 blocks      uint32_t        ref_block_prefix;       /// specifies the lower 32 bits of the block id at get_ref_blocknum      unsigned_int    max_net_usage_words = 0UL; /// number of 8 byte words this transaction can serialize into after compressions      uint8_t         max_cpu_usage_ms = 0UL; /// number of CPU usage units to bill transaction for      unsigned_int    delay_sec = 0UL; /// number of seconds to delay transaction, default: 0
      EOSLIB_SERIALIZE( transaction_header, (expiration)(ref_block_num)(ref_block_prefix)(max_net_usage_words)(max_cpu_usage_ms)(delay_sec) )   };

// eos/libraries/chain/transaction.cppvoid transaction_header::set_reference_block( const block_id_type& reference_block ) {   ref_block_num    = fc::endian_reverse_u32(reference_block._hash[0]);   ref_block_prefix = reference_block._hash[1];}
bool transaction_header::verify_reference_block( const block_id_type& reference_block )const {   return ref_block_num    == (decltype(ref_block_num))fc::endian_reverse_u32(reference_block._hash[0]) &&          ref_block_prefix == (decltype(ref_block_prefix))reference_block._hash[1];}// eos/libraries/chain/transaction_context.cppvoid transaction_context::init_for_input_trx_common( uint64_t initial_net_usage, bool skip_recording )   {      published = control.pending_block_time();      is_input = true;      const transaction& trx = packed_trx.get_transaction();      if (!control.skip_trx_checks()) {         control.validate_expiration(trx);         control.validate_tapos(trx);         validate_referenced_accounts( trx, enforce_whiteblacklist && control.is_producing_block() );      }      init( initial_net_usage );            if (!skip_recording)         record_transaction( packed_trx.id(), trx.expiration ); /// checks for dupes   }// eos/libraries/chain/controller.cppvoid controller::validate_tapos( const transaction& trx )const { try {   const auto& tapos_block_summary = db().get<block_summary_object>((uint16_t)trx.ref_block_num);
   //Verify TaPoS block summary has correct ID prefix, and that this block's time is not past the expiration   EOS_ASSERT(trx.verify_reference_block(tapos_block_summary.block_id), invalid_ref_block_exception,              "Transaction's reference block did not match. Is this transaction from a different fork?",              ("tapos_summary", tapos_block_summary));} FC_CAPTURE_AND_RETHROW() }

#include <eosio/transaction.hpp>#include <eosio/eosio.hpp>
using namespace eosio;
class [[eosio::contract("test")]] test: public contract {public:  using contract::contract;
  [[eosio::action]]  void checktapos() {    uint32_t current_block_num = tapos_block_num(); // 获取当前交易执行所在的区块号    uint32_t current_block_prefix = tapos_block_prefix(); // 获取当前交易执行所在的区块哈希前缀    print("ref_block_num: ", current_block_num,"\t\t\t");    print("ref_block_prefix: ", current_block_prefix);  }};

executed transaction: b35a59a178af7dedbbad641952146470adbe5e4d48316382afec5941fcdf2372  96 bytes  146 us#          test <= test::checktapos             "">> ref_block_num: 43983             ref_block_prefix: 448306994

root@VM-24-16-ubuntu:/home/ubuntu/biosboot/genesis# cleos get transaction b35a59a178af7dedbbad641952146470adbe5e4d48316382afec5941fcdf2372{  "id": "b35a59a178af7dedbbad641952146470adbe5e4d48316382afec5941fcdf2372",  "trx": {    "receipt": {      "status": "executed",      "cpu_usage_us": 146,      "net_usage_words": 12,      "trx": [        1,{          "compression": "none",          "prunable_data": {            "prunable_data": [              0,{                "signatures": [                  "SIG_K1_Jzmoz3cfi8H7tA3V8zidyihS7XYv29h1bnxdoFSM7ddvRXRo7q4GTJrgPKDsvbbXMFsaFxzCZeAqwwhG2GNVdjHXiL41y1"                ],                "packed_context_free_data": ""              }            ]          },          "packed_trx": "6b6eae64cfab329fb81a0000000001000000000090b1ca0000a6d56488544301000000000090b1ca00000000a8ed32320000"        }      ]    },    "trx": {      "expiration": "2023-07-12T09:12:11",      "ref_block_num": 43983,      "ref_block_prefix": 448306994,      "max_net_usage_words": 0,      "max_cpu_usage_ms": 0,      "delay_sec": 0,      "context_free_actions": [],      "actions": [{          "account": "test",          "name": "checktapos",          "authorization": [{              "actor": "test",              "permission": "active"            }          ],          "data": ""        }      ],      "signatures": [        "SIG_K1_Jzmoz3cfi8H7tA3V8zidyihS7XYv29h1bnxdoFSM7ddvRXRo7q4GTJrgPKDsvbbXMFsaFxzCZeAqwwhG2GNVdjHXiL41y1"      ],      "context_free_data": []    }  },  "block_time": "2023-07-12T09:11:41.500",  "block_num": 43985,  "last_irreversible_block": 44144,  "traces": [{      "action_ordinal": 1,      "creator_action_ordinal": 0,      "closest_unnotified_ancestor_action_ordinal": 0,      "receipt": {        "receiver": "test",        "act_digest": "f0d16f853ef72e7be5d8c84219cdcaa75d9b13d89b59c9385aebaecc20bc34f7",        "global_sequence": 43996,        "recv_sequence": 8,        "auth_sequence": [[            "test",            11          ]        ],        "code_sequence": 2,        "abi_sequence": 1      },      "receiver": "test",      "act": {        "account": "test",        "name": "checktapos",        "authorization": [{            "actor": "test",            "permission": "active"          }        ],        "data": ""      },      "context_free": false,      "elapsed": 39,      "console": "ref_block_num: 43983             ref_block_prefix: 448306994",      "trx_id": "b35a59a178af7dedbbad641952146470adbe5e4d48316382afec5941fcdf2372",      "block_num": 43985,      "block_time": "2023-07-12T09:11:41.500",      "producer_block_id": null,      "account_ram_deltas": [],      "account_disk_deltas": [],      "except": null,      "error_code": null,      "return_value_hex_data": ""    }  ]}