What is an idle loop in programming?

An idle loop refers specifically to a loop that does not perform any actions, meaning it has no code or instructions between its braces. This type of loop is generally used in programming contexts where the intention is to create an infinite loop that doesn't execute anything, allowing the program to actively wait or perform other tasks, such as managing system resources or waiting for an event without consuming processing power on any operations.

In contrast, other options introduce concepts that do not align with the fundamental definition of an idle loop. A loop that contains a single line of code could perform an action and is not considered idle because it is actively executing instructions. A loop used exclusively during competition might imply specific context but does not define the behavior or structure of an idle loop. Lastly, a loop that continuously runs until a condition is met implies it has some operation that eventually changes state, thus it is not idle since it fulfills a function by waiting for conditions to alter its course of execution.

Therefore, defining an idle loop as one that runs without any code between its braces precisely captures the essence of what constitutes an idle loop in programming.