Re: Java Threads

Hi,

When running on the server, your controller produces a 
hs_err_pidXXXX.log which you can download from your "files" page as 
hs_err_pid.zip. It tells us the following:

An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : 11 occurred at PC=0x4D212928
Function=glPushMatrix+0x0
Library=/usr/lib/libGL.so.1

Current Java thread:
        at com.cyberbotics.webots.Controller.robot_step(Native Method)
        at Sisyfus$actuators.run(Sisyfus.java:1363)
        - locked <0x4478c828> (a Sisyfus$actuators)
        at java.lang.Thread.run(Thread.java:534)

etc...

Which probably means that the libController is not thread safe, or 
maybe, you should use some mutex when using the Webots API functions (so 
that only one API call can be made at the same time) to avoid this 
problem. You were just lucky on your local machine to avoid this problem 
(threads often behave differently on different machines). If you can 
isolate which Webots API function are conflicting (and isolate them with 
mutexes), please let me know so that I can try to add mutexes inside the 
Webots API to avoid this problem in the future...

-Olivier

georgopl wrote:

>I am using a controller that has JAVA threads. At the momment it
>starts 2 threads, that should run concurrently. On my PC, the system
>runs perfectly. But, on the web the robot is totally frozen. Also,
>when I run it I get in my files section , a few files named
>hs_err_pidXXXX.log , where XXXX is a PID . These I cannot read. The
>error log shows no exceptions. 
>
>Why is it not running online? I have tested it on a few different
>machines and for both versions of webots. 4.027 and 5.01 . But no lack.
>
>I would really appreciate some help on this.
>
>
>
>Kindest regards
>
>Leonidas (Sisyfus)
>
>
>
>
>
>  
>


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