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

[Ruben Smits]

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
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