title: Linux: Cannot run popen command in C++ when not logged in
body: <p>EDIT: Changed the title as the problem was misunderstood. I run the application automatically at startup but this is not my problem. My problem is that I cannot run Linux system command using popen() when the application is started up automatically, as I try to explain below.</p>
  
  <p>I use popen() to run linux system command in a Qt C++ application to get information regarding my network connection, such as HW address, IP, mask, gateway, DHCP (if used).<br> To get this information I run the linux system command from my c++ code (assuming the ethernet adapter is eth0) : "nmcli dev list iface eth0". <br> This works fine in my test environment when I am (of course) logged in as a user.<br><br>
  However, the intention is that my application shall be set up to run right after boot in the background without the need to log in. This is working fine - my application starts after boot as expected.<br> BUT I am not able to run my Linux system command to get the network information I require. Is there any way to get around this? Can I call the system command from my c++ code in another manner or is there another way to get the required information?<br>
  The whole idea is that the application is run on a Linux box without the end-user having access the system, hence the reason for running without logging in.</p>