You want to run three tasks in parallel using fork and wait for all to finish. Which code correctly achieves this?

hard📝 Application Q8 of 15

Ruby - Concurrent Programming

You want to run three tasks in parallel using fork and wait for all to finish. Which code correctly achieves this?

A3.times { fork { puts 'Task' }; Process.wait }

Bpids = 3.times.map { fork { puts 'Task' } }; Process.waitall(pids)

C3.times.map { fork { puts 'Task' } }; Process.wait

Dpids = 3.times.map { fork { puts 'Task' } }; pids.each { |pid| Process.wait(pid) }

Step-by-Step Solution

Solution:

Step 1: Fork three child processes and collect PIDs
Using 3.times.map { fork { ... } } stores child PIDs in an array.
Step 2: Wait for each child process individually
Iterate over PIDs and call Process.wait(pid) to wait for each child.
Final Answer:
pids = 3.times.map { fork { puts 'Task' } }; pids.each { |pid| Process.wait(pid) } -> Option D
Quick Check:
Fork multiple and wait each PID = pids = 3.times.map { fork { puts 'Task' } }; pids.each { |pid| Process.wait(pid) } [OK]

Quick Trick: Collect PIDs, then wait each to sync parallel tasks [OK]

Common Mistakes:

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