To report a bug, can not transfer usd. Check the source code, it may due to the different unit between total_in (default bts) and itr->second.get_amount() (here is usd)
I might try to provide pull request if I can fix it.
console:
>>> transfer 3 usd to MpeitToLdKLLnee9iBKnU7enQ6z
assert
unit == o.unit:
{}
th_a asset.cpp:110 bts::blockchain::asset::operator +=
3.00000000 usd to MpeitToLdKLLnee9iBKnU7enQ6z
{"amnt":"3.00000000 usd","to":"MpeitToLdKLLnee9iBKnU7enQ6z"}
th_a blockchain_wallet.cpp:324 bts::blockchain::wallet::transfer
log.txt: (stop when iterate to first usd unspend)
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"6e737d784bd476afc4fda36b9cda4b44ff34d41a","output_idx":3},{"amount":100000000,"unit":"bts","claim_func":"claim_by_cover","claim_data":{"payoff_unit":"usd","payoff_amount":500000000,"owner":"Kjis77t43i41LmrUJ7rWeJrdwwe"}}] blockchain_wallet.cpp:84
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"4b008fb75fb67eaa59b3c1393ca2e187487123a0","output_idx":0},{"amount":50000000,"unit":"usd","claim_func":"claim_by_bid","claim_data":{"pay_address":"SJyXwKU2Mmy3Z7Fxw5ia8VLYxre","ask_price":"0.5000000000000 usd/bts","min_trade":0}}] blockchain_wallet.cpp:84
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"60ab5e3d73f9d31b5b9e49fadaf3f383663cff89","output_idx":0},{"amount":100000000,"unit":"usd","claim_func":"claim_by_bid","claim_data":{"pay_address":"MiJq5cKVpwcjAb1DMhihaDEsyP8","ask_price":"50.0000000000000 usd/bts","min_trade":0}}] blockchain_wallet.cpp:84
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"5d617e24a41aca2401d28ea85ec3f4f9ae6e120b","output_idx":0},{"amount":10000000,"unit":"bts","claim_func":"claim_by_bid","claim_data":{"pay_address":"RQQgPKGEGzzL6izqPKcWzdvbuFu","ask_price":"80.0000000000000 usd/bts","min_trade":0}}] blockchain_wallet.cpp:84
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"6e737d784bd476afc4fda36b9cda4b44ff34d41a","output_idx":2},{"amount":50000000,"unit":"bts","claim_func":"claim_by_long","claim_data":{"pay_address":"Kjis77t43i41LmrUJ7rWeJrdwwe","ask_price":"10.0000000000000 usd/bts","min_trade":0}}] blockchain_wallet.cpp:84
2212718ms th_a collect_inputs ] unspent outputs [{"trx_hash":"55a250e2e249107583085457b5e7d2bebe5b7531","output_idx":1},{"amount":1000000000,"unit":"usd","claim_func":"claim_by_signature","claim_data":{"owner":"Jvo7Xfow3xVToALbVHKPa3UVYRw"}}] blockchain_wallet.cpp:84