Store enum value in table

Question

I have a simple enum (or enum class, neither one is working )

enum vote_option {
  upvote = 0,
  downvote

and a table which will store a value of that enum type.

struct [[eosio::table]] poll
{
  uint64_t key;
  vote_option opt;

  uint64_t primary_key() const { return key; }
};

And the problem is the build is fine, but when I even get table I've got

Error 3015004: The type defined in the ABI is invalid
Error Details:
vote_option

Has anyone experienced this kind of problem ?

I use eosio.cdt v 1.6.2 and eosio v1.8.4 .

Answer 1

If you use a custom type you must also define the type to a built in type. A list of accepted types by EOSIO can be found here, https://eosio.stackexchange.com/a/1932/3333.

For instance, your custom enum is actually a uint8_t type.

You'll need something like ..

## header file

enum e_vote_option {
  upvote = 0,
  downvote
}

typedef uint8_t vote_option;

struct [[eosio::table]] poll
{
  uint64_t key;
  vote_option opt;

  uint64_t primary_key() const { return key; }
};

### source file

vote_table.emplace(_self, [&](auto& o) {
    o.key = vote_table.available_primary_key();
    o.opt = e_vote_option::downvote;
});

With this format, your ABI file will correctly set vote_option as uint8_t.