I'm absolutely sure I know what I do (20 years under linux/minix)^^
I start an root terminal and i type "codeblock>nul&"
Why do you use wrong syntax, with that background ?
First: the executable is named
codeblocks (surely a typo),
second:
nul is not a valid device in linux, but (if I remember correctly) on windows, you write in a file named
nul,
third, why do you move C::B in the background, is there any reason for doing so ?
What I can say: if C::B is started from a console (or more exactly: from inside a virtual terminal started by me as normal-user) it is no problem to debug ncurses on my debian machine(s).
And if working as root is absolutely necessary, it's (in most cases) better to run the commands with sudo instead of using a root-terminal, where each command runs with root-privileges, because it's less error-prone.
But that's just my opinion, after (also) 20 years under linux, hp-unx, sinix, dos and windows.