Solidity compiler: Type void is not implicitly convertible to expected type string memory.

brandonzfr

I am trying to build a simple contract where contract A has a function that just returns the first item in an array stored in another contract B. I keep receiving the following error. It does not seem to like strings!

Type error: Type void is not implicitly convertible to expected type string memory.
return contractB.getAttributeZero();

contract B {
    string[10] attributes;
    function B() {
        attributes[0] = "Pets";
    }
    function getAttributeZero() constant returns(string) {
        return attributes[0];
    }
}


contract A {
  function getAttribute() constant returns(string) {
    B contractB = new B();
    return contractB.getAttributeZero();
  }
}

chriseth

EVM calls cannot return dynamically sized objects as a limitation of the virtual machine.
They can, on the other hard, return dynamically-sized objects to the "outside".

brandonzfr

@chriseth Thanks for the fast reply! Is there a recommended way around this issue. Are there fixed sized strings or something I can use? I saw string32 mentioned somewhere but this doesn't seem to exist any longer.

chriseth

You have to use raw bytes (i.e. bytes32) and there is no conversion to string yet.