FAQ

How to interact with CPChain?

You can utilize cpc_fusion to interact with CPChain in a python interpreter.

>>> from cpc_fusion import Web3
>>> cf = Web3(Web3.HTTPProvider('http://127.0.0.1:8501'))
>>> cf.cpc.blockNumber
34341

Why does fusion return an error (Errno 111) indicating connection is refused?

The Errno 111 can be returned when you call Web3(Web3.HTTPProvider('http://127.0.0.1:8501')) in fusion.

Before connecting http://127.0.0.1:8501, you should either set up a local chain or sync with our Mainnet. Refer to Using Fusion to detailed explanations.

Why ./cpchain run command cannot be executed successfully?

Several reasons can account for this problem. You may try the following means to solve the problem.

  1. Confirm that you are connecting to the network and the ports you nominated are available.

If you use the command in Quick Start in Detail as

$ ./cpchain run --rpcaddr 127.0.0.1:8501 --port 30311

, make sure both port 8501 and 30311 have not be occupied yet. You may also use other ports as you wish.

  1. Remove temporary user files.

The existence of some temporary files get cpchain skip some initialization processes, which may result in an unsuccessful execution.

Type in the following to remove temporary files.

$ ./cpchain chain cleandb
  1. Manually kill all cpchain processes.

An incomplete abort of cpchain can incur a failure in starting a new process. If you receive an error message indicating your port or datadir being occupied, it is highly possible that there are some cpchain processes still running in background.

You can may either use ps command paired with kill to terminate cpchain processes, or choose to kill all cpchain processes by

$ killall -9 cpchain

Message The file "./cpchain" is not executable by this user pops when running cpchain

This problem is due to a wrong access permission of the binary file. You can fix this problem by using the command below:

$ chmod +x cpchain

Message Fatal: Failed to unlock account pops when running cpchain

One possible reason is that the account file is not in the right directory.

In the command

$ ./cpchain run --datadir ./datadir \
    --unlock WALLET_ADDRESS \
    --rpcaddr 127.0.0.1:8501 --port 30311 --mine \
    --rpcapi personal,eth,cpc,admission,net,web3,db,txpool,miner --linenumber

--datadir ./datadir means the account file (keystore) in under ./datadir directory. If you create an account without specify a directory, like using the command ./cpchain account new account instead of ./cpchain account new account --datadir ./datadir, the account file is created under a default directory, which is not ./datadir.

In this case, you can either

  • Specify YOUR_ACCOUNT_DIRECOTRY after --datadir, or
  • Move your account file to ./datadir.

Message error  while  loading  shared  libraries:  libz3.so.4 pops when running solc

It can be resolved by running the command below:

$ sudo  apt-get  install  libz3-dev

The default solc is not a compatible version

To check the version of solidity, you may utilize the following command:

$ solc --version

And by using $ which solc command, you can locate the path for default solc, and replace it with a 0.4.25 version.

$ which solc
/usr/bin/solc
$ rm -f /usr/bin/solc
// copy solc 0.4.25 to /user/bin
$ cp solc /usr/bin