# Precondition > In programming, a precondition is a set of conditions that must hold for a particular section of code (usually a function) to execute correctly. In , a precondition is a set of conditions that must hold for a particular section of code (usually a function) to execute correctly. ## See also - - - : A design approach that makes the semantics of preconditions, postconditions, and invariants concrete through the concept of a "contract." - [Guard clauses](https://wiki.g15e.com/en/pages/Guard%20clauses.txt): Explicitly checking preconditions at the start of a function.