c26110.md

description	title	ms.date	ms.topic	f1_keywords	helpviewer_keywords	ms.assetid
Learn more about: C26110	C26110	10/01/2019	reference	C26110	C26110	d82b79ec-6d7f-438b-bd6a-da874a3e08e5

C26110

warning C26110: Caller failing to hold lock <lock> before calling function <func>.

When a lock is required, make sure to clarify whether the function itself or its caller should acquire the lock. Warning C26110 is issued when there is a violation of the _Requires_lock_held_ annotation, or other lock-related annotations. For more information, see Annotating Locking Behavior

Example

In the following example, warning C26110 is generated because the annotation _Requires_lock_held_ on function LockRequired states that the caller of LockRequired must acquire the lock before it calls LockRequired. Without this annotation, LockRequired has to acquire the lock before it accesses any shared data protected by the lock.

typedef struct _DATA
{
    CRITICAL_SECTION cs;
    int d;
} DATA;

_Requires_lock_held_(p->cs)

void LockRequired(DATA* p)
{
    p->d = 0;
}

void LockNotHeld(DATA* p)
{
    LockRequired(p); // Warning C26110
}