That's only true in C++ though, not in C.
C does allow unconditional infinite loops (e.g. "while (1) { }" isn't UB) but still is UB if the controlling expression isn't constant (e.g. "while (two < 10) { }" is UB if two is a variable less than 10)
C does allow unconditional infinite loops (e.g. "while (1) { }" isn't UB) but still is UB if the controlling expression isn't constant (e.g. "while (two < 10) { }" is UB if two is a variable less than 10)