Lanes concurrency

Hi,

I have a problem with using different lanes to start commands with popen simultaneously. The read()s seems to block all other lanes resulting in a sequential behaviour?

To reproduce, run:

require("lanes")

function run(i)

local file = io.popen("sleep 5", "r")

-- local output = file:read("*a")

file:close()

print("finished " .. i)

end

local measurements = {}

local lane = lanes.gen("*", run)

for second = 0, 10 do measurements[second] = lane(second) end

for second = 0, 10 do measurements[second]:join() end

# time ./test.lua

finished 1

finished 0

finished 3

finished 4

finished 5

finished 2

finished 9

finished 6

finished 7

finished 10

finished 8

real 0m5.016s ßpopen sleeps are executed in parallel, which to me is the expected behaviour

Then uncomment the file:read() line and run again