Time of Check to Time of Use

• a.k.a.: TOCTTOU

• Described by Wikipedia:

        In software development, time of check to time of use ... is a class of
        software bug caused by changes in a system between the checking of a condition
        ... and the use of the results of that check. This is one example of a race
        condition.

        ...

        TOCTTOU race conditions are most common in Unix between operations on the
        file system, but can occur in other contexts, including local sockets and
        improper use of database transactions.

        [A]pplications cannot assume the state managed by the operating system
        will not change between system calls.