warning C26115: Failing to release lock <lock> in function <func>.

Enforcement of syntactically scoped lock acquire and lock release pairs in C/C++ programs is not performed by the language. A function may introduce a locking side effect by making an observable modification to the concurrency state. For example, a lock wrapper function increments the number of lock acquisitions, or lock count, for a given lock.

You can annotate a function that has a side effect from a lock acquire or lock release by using _Acquires_lock_ or _Releases_lock_, respectively. Without such annotations, a function is expected not to change any lock count after it returns. If acquires and releases are not balanced, they are considered to be orphaned. Warning C26115 is issued when a function introduces an orphaned lock.


The following example generates warning C26115 because there is an orphaned lock in a function that is not annotated with _Acquires_lock_.

typedef struct _DATA 

void FailToReleaseLock(int flag, DATA* p) 

    if (flag)
        return; // Warning C26115