1 files changed, 30 insertions, 0 deletions
diff --git a/code/snippets/signals_chld_naive.rb b/code/snippets/signals_chld_naive.rb
new file mode 100644
index 0000000..59929fb
--- /dev/null
+++ b/code/snippets/signals_chld_naive.rb
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+child_processes = 3
+dead_processes = 0
+# We fork 3 child processes.
+child_processes.times do
+  fork do
+    # They sleep for 3 seconds.
+    sleep 3
+  end
+end
+
+# Our parent process will be busy doing some intense mathematics.
+# But still wants to know when one of its children exits.
+
+# By trapping the :CHLD signal our process will be notified by the kernel
+# when one of its children exits.
+trap(:CHLD) do
+  # Since Process.wait queues up any data that it has for us we can ask for it
+  # here, since we know that one of our child processes has exited.
+  
+  puts Process.wait
+  dead_processes += 1
+  # We exit explicitly once all the child processes are accounted for.
+  exit if dead_processes == child_processes
+end
+
+# Work it.
+loop do
+  (Math.sqrt(rand(44)) ** 8).floor
+  sleep 1
+end