[ros-users] Non-blocking version of ros::init()?

[Ken Conley]

I can't help with the assertion question, but to answer your other question:

While you *could* start your own master using popen, I really don't
recommend that you should. Tools like roslaunch already provide this
behavior for nodes, and it's generally a bad idea for nodes to take it
upon themselves to do this.  ROS generally assumes that it's okay to
launch many nodes simultaneously and in arbitrary order. If nodes
encode their own logic for launching masters, chaos would result.

 - Ken

On Sun, Sep 12, 2010 at 5:59 AM, Ruben Smits
<ruben.smits at mech.kuleuven.be> wrote:
> On Saturday 11 September 2010 20:03:48 Josh Faust wrote:
>> init() shouldn't be blocking -- if it does it's a bug.  It's designed this
>> way so you can call ros::master::check().  Creation of the first
>> NodeHandle or calling start() should be what's blocking.
>
> Ok, sorry for the mistake, it was indeed ros::start() that blocked my code. I
> changed it into the following:
>
> bool loadRTTPlugin(RTT::TaskContext* c){
>    log(Info)<<"Initializing ROS node"<<endlog();
>    if(!ros::isInitialized()){
>      int argc=0;
>      char* argv[0];
>      ros::init(argc,argv,"rtt",ros::init_options::AnonymousName);
>      if(ros::master::check())
>          ros::start();
>      else{
>          log(Error)<<"No ros::master available"<<endlog();
>          return false;
>      }
>    }
>    static ros::AsyncSpinner spinner(1); // Use 1 threads
>    spinner.start();
>    log(Info)<<"ROS node spinner started"<<endlog();
>    return true;
>  }
>
> But now I get the the following assertion:
>
> 0.719 [ ERROR  ][DeploymentComponent::import] No ros::master available
> 0.719 [ ERROR  ][DeploymentComponent::import] Failed to load RTT Plugin
> 'ros_integration': plugin refused to load into this process. Unloading.
> deployer-gnulinux: /usr/include/boost/thread/pthread/mutex.hpp:50: void
> boost::mutex::lock(): Assertion `!pthread_mutex_lock(&m)' failed.
>
> Program received signal SIGABRT, Aborted.
> 0x00007ffff4caca75 in *__GI_raise (sig=<value optimized out>)
>    at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
> 64      ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
>        in ../nptl/sysdeps/unix/sysv/linux/raise.c
> (gdb) bt
> #0  0x00007ffff4caca75 in *__GI_raise (sig=<value optimized out>)
>    at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
> #1  0x00007ffff4cb05c0 in *__GI_abort () at abort.c:92
> #2  0x00007ffff4ca5941 in *__GI___assert_fail (
>    assertion=0x7ffff124f7e5 "!pthread_mutex_lock(&m)",
>    file=<value optimized out>, line=50,
>    function=0x7ffff124f9a0 "void boost::mutex::lock()") at assert.c:81
> #3  0x00007ffff12453db in boost::mutex::lock (loc=0x7ffff1beea20,
>    name=..., level=ros::console::levels::Debug)
>    at /usr/include/boost/thread/pthread/mutex.hpp:50
> #4  boost::unique_lock<boost::mutex>::lock (loc=0x7ffff1beea20, name=...,
>    level=ros::console::levels::Debug)
>    at /usr/include/boost/thread/locks.hpp:338
> #5  unique_lock (loc=0x7ffff1beea20, name=...,
>    level=ros::console::levels::Debug)
>    at /usr/include/boost/thread/locks.hpp:224
> #6  ros::console::initializeLogLocation (loc=0x7ffff1beea20, name=...,
>    level=ros::console::levels::Debug)
>    at /opt/ros/cturtle/ros/core/rosconsole/src/rosconsole/rosconsole.cpp:6---
> Type <return> to continue, or q <return> to quit---
> 10
> #7  0x00007ffff1923e4a in ros::atexitCallback ()
>    at /opt/ros/cturtle/ros/core/roscpp/src/libros/init.cpp:149
> #8  0x00007ffff4cb2630 in __cxa_finalize (d=0x7ffff1bee000)
>    at cxa_finalize.c:56
> #9  0x00007ffff18f23d6 in __do_global_dtors_aux ()
>   from /opt/ros/cturtle/ros/core/roscpp/lib/libros.so
> #10 0x0000000000000015 in ?? ()
> #11 0x00007fffffffc8d0 in ?? ()
> #12 0x00007ffff19abc81 in _fini ()
>   from /opt/ros/cturtle/ros/core/roscpp/lib/libros.so
> #13 0x0000000000000032 in ?? ()
> #14 0x00007ffff7df0972 in _dl_close_worker (map=<value optimized out>)
>    at dl-close.c:271
> #15 0x0000000000680f80 in ?? ()
>
> Another question:
>
> Would it be possible to start my own master if none is available? Can it be
> done using ros::master::init()?
>
> Ruben
>> Josh
>>
>> On Sat, Sep 11, 2010 at 7:53 AM, Ruben Smits
>> <ruben.smits at mech.kuleuven.be<mailto:ruben.smits at mech.kuleuven.be>> wrote:
>> Hi,
>>
>> I would like to know if there is a way to call ros::init and not block
>> untill a ros::master is available but just return an error or the like if
>> a ros::master is not available so that my code can continue.
>>
>> Ruben
>> _______________________________________________
>> ros-users mailing list
>> ros-users at code.ros.org<mailto:ros-users at code.ros.org>
>> https://code.ros.org/mailman/listinfo/ros-users
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>