How to use setenv() to export a variable in c++?

Question

I need to export several variables such that they look like the following in the command line

export ROS_HOSTNAME=xxx

How do I use setenv()

Answer 1

Here the signature for the setenv function

#include 

int setenv(const char *envname, const char *envval, int overwrite);

Link : http://pubs.opengroup.org/onlinepubs/009695399/functions/setenv.html

In your case you call it like this:

setenv("ROS_HOSTNAME", "xxx", true);

the last boolean argument indicates if you want to overwrite the value of the environment variables if it already exists.