Solidity Gas Requirement – Understanding Infinite Gas in Functions

mappingremixsolidity

struct userData{
     uint val;
     bool isvalue;
     string name;
}



mapping(uint => address) internal users;
mapping(address => userData) internal bidirectionalUsers;

function addMember(address newMember, string memberName) public{

        if (msg.sender != owner) return;

        if (bidirectionalUsers[newMember].isvalue) return;

        users[memberCount] = newMember;
        bidirectionalUsers[newMember] = userData(memberCount,true,memberName);

    }

Above code is throwing warning in addMember(), gas limit is high:infinite and it can not be executed.

I commented all the lines inside the function but still it throws this warning. What I'm doing wrong here? Can somebody help me in this. Thank you.

Best Answer

You can safely ignore this warning. The problem is your string variable in the parameters string memberName. Because a string has no fixed size, it is theoretically possible to require an infinite amount of gas to fill it with an infinite amount of characters.

Your code will still compile and work if no other errors are being shown.

Related Solutions

[Ethereum] Solidity function that accepts mapping as input

You can't pass the whole mapping. You could pass a struct internally. Ideally, you would enumerate the fields you really need to pass so you can create an interface that works with other contracts and clients.

Your example above, seems to pass a single member of the source mapping. I would interpret that roughly like this:

pragma solidity ^0.4.6;

contract testInputArray {

    mapping (string => string) aMapping;

    // Log event to print the message details
    event Log(address from, address to, string message);

    function sendMessage(address to, string key) {
        Log(msg.sender, to, aMapping[key]);
    }
}

Hope it helps.

P.S. It would be remiss to omit the usual preference for bytes32 over string if that's possible in this case. Left it as string for clarity.

Solidity – Handling Unimplemented Functions in Contracts

The problem is that totalSupply() implementation is missing. Seems like autogenerated getters do not count. So you need to explicitly create the function.

contract StandardToken is Token {
    uint256 _totalSupply;

    function totalSupply() constant returns (uint256 totalSupply) {
        totalSupply = _totalSupply;
    }
}

Best Answer

Related Solutions

[Ethereum] Solidity function that accepts mapping as input

Solidity – Handling Unimplemented Functions in Contracts

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