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POHandle a blocking function call in Python
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  1. POHandle a blocking function call in Python
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    copied!<p>I'm working with the <a href="http://gnuradio.org/redmine/wiki/gnuradio" rel="nofollow">Gnuradio framework</a>. I handle flowgraphs I generate to send/receive signals. These flowgraphs initialize and start, but they don't return the control flow to my application:</p> <p>I imported <code>time</code></p> <pre><code>while time.time() &lt; endtime: # invoke GRC flowgraph for 1st sequence if not seq1_sent: tb = send_seq_2.top_block() tb.Run(True) seq1_sent = True if time.time() &lt; endtime: break # invoke GRC flowgraph for 2nd sequence if not seq2_sent: tb = send_seq_2.top_block() tb.Run(True) seq2_sent = True if time.time() &lt; endtime: break </code></pre> <p>The problem is: only the first if statement invokes the flow-graph (that interacts with the hardware). I'm stuck in this. I could use a Thread, but I'm unexperienced how to timeout threads in Python. I doubt that this is possible, because it seems killing threads isn't within the APIs. This script only has to work on Linux...</p> <p>How do you handle blocking functions with Python properly - without killing the whole program. Another more concrete example for this problem is:</p> <pre><code>import signal, os def handler(signum, frame): # print 'Signal handler called with signal', signum #raise IOError("Couldn't open device!") import time print "wait" time.sleep(3) def foo(): # Set the signal handler and a 5-second alarm signal.signal(signal.SIGALRM, handler) signal.alarm(3) # This open() may hang indefinitely fd = os.open('/dev/ttys0', os.O_RDWR) signal.alarm(0) # Disable the alarm foo() print "hallo" </code></pre> <p>How do I still get <code>print "hallo"</code>. ;)</p> <p>Thanks, Marius</p>
 

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