Is there a C++ equivalent to roslib.get_ros_home() ?

asked 2014-02-09 05:23:09 -0600

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updated 2016-10-24 09:01:11 -0600

ngrennan
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In python, it's possible to use roslib.get_ros_home() to query the environment for the ROS_HOME environment variable, and fall back to HOME/.ros if it doesn't exist. This is very useful for finding a directory that ROS processes can use for storing their own logs or other temporary data.

Is there any equivalent to this in C++?

answered 2014-02-09 16:21:02 -0600

Martin Peris
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Hi there!

Inside roscpp/src/libros/file_log.cpp they use:

std::string ros_log_env;
get_environment_variable(ros_log_env, "ROS_HOME")

But I wasn't able to figure out where get_environment_variable comes from (is it a system call? is it a custom fucntion?... no idea).

I hope this hint would help you

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Comments

Thanks! I suspect the get_environment_variable uses the standard C `getenv` function somewhere underneath. Looking into file_log.cpp some more, it looks like they're implementing the fallback logic by hand rather than using a library function for it. I suspect I'll have to do the same in my code.

ahendrix ( 2014-02-09 16:49:10 -0600 )edit

For the record, comes from roscpp_core/cpp_common/include/ros/platform.h

Daniel Stonier ( 2014-08-30 08:08:36 -0600 )edit

Hi Daniel, thanks for pointing that out! Could you, please, check the link that you posted? It currently points to http://answers.ros.org/question/12760... instead of the file that you mention. Thanks!