[ros-users] First Message Missing

David Lu!! davidlu at wustl.edu
Sun Sep 12 22:34:14 UTC 2010

Hey all,
I'm not quite sure if this is a bug, or if it is, where to file it,
but it took me forever to track down the problem.

Here's my test program based on rospy tutorials. (I'm using C-Turtle
binaries on 10.04)
import roslib; roslib.load_manifest('crazy')
import rospy
from std_msgs.msg import String

def talker():
    pub = rospy.Publisher('chatter', String)
    rospy.init_node('talker', anonymous=True)
    str = "hello world"

if __name__ == '__main__':
    except rospy.ROSInterruptException: pass

Fairly standard, and it works like you would expect. However, if you
switch the order of 7th and 8th lines, i.e.
    rospy.init_node('talker', anonymous=True)
    pub = rospy.Publisher('chatter', String)
...it does NOT publish the message.

However, when I add a sleep(1) command after Publisher line, then it
works fine.

Is this...
A) A bug
B) A situation where I should just sleep
C) A situation where I should publish the message repeatedly until I'm
sure it's received.


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