add examples/multiple_threads.py

examples/multiple_threads.py

+import sys
+import gevent
+from gevent import monkey
+
+
+start_new_thread = monkey.get_unpatched('thread', 'start_new_thread')
+
+
+def _run(func, args, kwargs, async, result):
+    try:
+        value = func(*args, **kwargs)
+        result.append((True, value))
+    except:
+        result.append((False, sys.exc_info()))
+    finally:
+        async.send()
+
+
+def _run_in_thread(func, *args, **kwargs):
+    hub = gevent.get_hub()
+    async = hub.loop.async()
+    result = []
+    start_new_thread(_run, (func, args, kwargs, async, result))
+    hub.wait(async)
+    return result[0]
+
+
+def run_in_thread(func, *args, **kwargs):
+    succeeded, result = _run_in_thread(func, *args, **kwargs)
+    if succeeded:
+        return result
+    else:
+        raise result
+
+
+if __name__ == '__main__':
+    import os
+    import time
+    start = time.time()
+    for _ in xrange(4):
+        gevent.spawn(run_in_thread, os.system, 'sleep 1')
+    gevent.run()
+    delay = time.time() - start
+    print 'Running "sleep 1" 4 threads. Should take about a second: %.2fs' % delay