Share ETS table with two processes?

Question

I create ETS table in one process and I want use it in another process. How I "open" ETS table in second process? Could not find good function in man pages.

Answer 1

you have to create ets table with 'named_table' and 'public' options.

like

T = ets:new(yourtablename,[public,named_table]).

in that case other local processes can use this table by name 'yourtablename'. It's not necessary to explicitly open this table in other processes.

Answer 2

If you don't want your table to have a unique name, you can omit named_table and just use public. Then ets:new will return an integer that you need to pass to the process that needs to access the table:

-module(foo).
-compile(export_all).

create_the_table(Pid) ->
    Table = ets:new(mytable, [public]),
    ets:insert(Table, {foo, bar}),
    Pid ! {the_table_is, Table},
    timer:sleep(infinity).

use_the_table() ->
    receive {the_table_is, Table} -> ok end,
    io:format("~p~n", [ets:lookup(Table, foo)]).

Try it from the shell:

2> c(foo).
{ok,foo}
3> Pid1 = spawn(foo, use_the_table, []).
<0.43.0>
4> spawn(foo, create_the_table, [Pid1]).
[{foo,bar}]
<0.45.0>