Transaction net gain/loss

Question

I have a TXid in my wallet that contains multiple transactions (multiple sends and receives). From what I read these are transactions the network creates facilitate splitting/combining multiple inputs/outputs etc. When I gettransaction in the wallet I have I see

gettransaction 3dda59bf9801f88...5498dd7fd1c3f9577963b94
{
  "amount": -17.00000000,
  "fee": 20.00000000,

  "details": [
    {
      "account": "",
      "category": "send",
      "amount": 0.00000000,
      "vout": 0,
      "fee": 20.00000000
    },
    {
      "account": "",
      "address": "GPP7ic67...9TgitCB21r",
      "category": "send",
      "amount": -20.00000000,
      "vout": 1,
      "fee": 20.00000000
    },
    {
      "account": "",
      "address": "GPP7ic67...9TgitCB21r",
      "category": "send",
      "amount": -17.00000000,
      "vout": 2,
      "fee": 20.00000000
    },
    {
      "account": "TestWallet",
      "address": "GPP7ic67...9TgitCB21r",
      "category": "receive",
      "amount": 20.00000000,
      "vout": 1
    }
  ],

So, I'm trying to figure out what the net result of this transaction is. I received -17 and I had 20 fee. Does that mean I net loss 37?

Answer 1

hmmm, yes, this accounting system within bitcoin :-) bitcoin.SE is full of questions according to the balance on accounts.

The "-17" would indicate, that funds left from a known address in your wallet to an "external" target address. And if fees is 20, then yes, you have "outgoing" 37 coins. Btw: what system are you playing on? Addresses starting with "GPP"...?

When I was playing with the regtest env, I discovered that only "gettxout" provides reliable info, which tx might have funds. See also the thread here.

Here a short linux shell script, to fetch the idea. It needs to get updated to cope with many inputs, so one would need to iterate through the VINs...

  b_cli="bitcoind -regtest"
  FUNDING_TXID=3dda59bf9801f88...5498dd7fd1c3f9577963b94

  TX_PREV_VOUT=$( $b_cli gettransaction $FUNDING_TXID | \
                  awk '/vout/ {  print $2; exit }'    | tr -d "," )

  $b_cli gettxout $FUNDING_TXID $TX_PREV_VOUT

  # as per Pieter's comment, spendable VINs return "something"...
  if [ ${#ret_val} -gt 0 ]; then
    echo " ## This tx has spendable funds"
  else
    echo " ## no spendable funds on $FUNDING_TXID"
  fi

Adding up all the parts, which have spendable funds, would then be "your" balance. And you could check "in" and "out" going funds in your wallet.