A redditor posted in r/learnprogramming
Why did Bjarne Stroustrup not get into copyright trouble with Dennis Ritchie, for basically copying C and adding his new features?
u/bstroustrup replied
Why should Dennis have complained? He helped me. The "const" design is partly his and he gave me the troff source of the C manual to use as a starting point for the C with Classes manual. Bell Labs Computer Science Research Lab was quite a friendly environment.