-module(processes).
-export([max/1]).

%% max(N)
%% Create N processes then destroy them
%% See how much time this takes
max(N) ->
    Max = erlang:system_info(process_limit),
    io:format("Maximum allowed processes:~p~n" ,[Max]),
    statistics(runtime),
    statistics(wall_clock),
    L = for(1, N, fun() -> spawn(fun() -> wait() end) end),
    {_, Time1} = statistics(runtime),
    {_, Time2} = statistics(wall_clock),
    lists:foreach(fun(Pid) -> Pid ! die end, L),
    U1 = Time1 * 1000 / N,
    U2 = Time2 * 1000 / N,
    io:format("Process spawn time=~p (~p) microseconds~n" ,
              [U1, U2]).
wait() ->
    receive
        die -> void
    end.

for(N, N, F) -> [F()];
for(I, N, F) -> [F()|for(I+1, N, F)].