Reading has_realtime fails sometimes

[axelschroth]

I think this line should be changed from

Universal_Robots_ROS_Driver/ur_robot_driver/src/hardware_interface_node.cpp

Line 60 in 783b1d1

bool has_realtime;

to

bool has_realtime = false;

I noticed that if I modify some unrelated code without initializing has_realtime, printing has_realtime sometimes outputs a number like e.g. 168 or 66. I suspect the ifstream to do nothing if /sys/kernel/realtime does not exist.
Any thoughts on that strange behavior?

[fmauch]

Using the stream's fail() or good() functions might be reasonable. I've wanted to refactor this code for quite some time to also allow setting a higher thread priority if no realtime capability is found.

Initializing the variable and checking the ifstream might be a good first start to address the issue you mentioned.

Something like

std::ifstream realtime_file("/sys/kernel/realtime", std::ios::in);
bool has_realtime = false;
if (realtime_file.good())
{
  realtime_file >> has_realtime;
}

@axelschroth could you maybe test whether this works for you?

[axelschroth]

Following works for me using is_open():

std::ifstream realtime_file("/sys/kernel/realtime", std::ios::in);
bool has_realtime = false;
if (realtime_file.is_open())
{
  realtime_file >> has_realtime;
}

[axelschroth]

Sorry for the confusion above. I created a PR.

[fmauch]

This should have been fixed with #311 -> closing this issue.