What's the best practice about multiple subscribers and publishers?

[fwxnn]

I met a question recently. When I use the same object lcm::LCM lcm to subscribe and publish different channels in the same time, it's easy to cause core dump. e.g.

"""
lcm::LCM lcm;
lcm.subscribe("channel A", …)
lcm.subscribe("channel B", …)

while(lcm.good())
{
lcm.publish("channel A", …)
lcm.handle();
lcm.publish("channel B", …)
lcm.handle();
}
"""

My test platform is ubuntu 18.04 with x64 architecture. Looking forward to your early reply since lcm is planned to ba applied to our true program. thx!

[nosracd]

Is it possible the segfaults are occurring in the callbacks you're registering? As far as I can tell, the pseudocode you posted should work fine. For example, this Python script:

import lcm

def callback(channel, message):
    print(f'Received message on channel {channel}')

lcm_object = lcm.LCM()
lcm_object.subscribe('channel A', callback)
lcm_object.subscribe('channel B', callback)

lcm_object.publish('channel A', bytes(0))
lcm_object.handle()

lcm_object.publish('channel B', bytes(0))
lcm_object.handle()

produces the output:

Received message on channel channel A
Received message on channel channel B

[fwxnn]

Indeed it works! I have found the question I made and LCM works quite well! THX