---
description: "Learn more about: Warning C26105"
title: Warning C26105
ms.date: 11/04/2016
f1_keywords: ["C26105"]
helpviewer_keywords: ["C26105"]
ms.assetid: 5558a3db-0513-43b4-8579-ccdc17e2b92f
---
# Warning C26105

> Lock order violation. Acquiring lock '*lock*' with level '*level*' causes order inversion.

Concurrency SAL supports *lock levels*. To declare a lock level, which is denoted by a string literal without double quotes, use `_Create_lock_level_`. You can impose an order of acquisition between two lock levels by using the annotation `_Set_lock_level_order_(A,B)`, which states that locks that have level `A` must be acquired before locks that have level `B`. To establish a lock order hierarchy (a partial order among lock levels), use multiple `_Set_lock_level_order_` annotations. To associate a lock with a lock level, use the `_Set_lock_level_` annotation when you declare the lock. Warning C26105 is issued when a lock ordering violation is detected.

## Example

The following example generates warning C26105 because there's a lock order inversion in the function `OrderInversion`.

```cpp
_Create_lock_level_(MutexLockLevel);
_Create_lock_level_(TunnelLockLevel);
_Create_lock_level_(ChannelLockLevel);
_Lock_level_order_(MutexLockLevel, TunnelLockLevel);
_Lock_level_order_(TunnelLockLevel, ChannelLockLevel);
_Has_lock_level_(MutexLockLevel) HANDLE gMutex;

struct Tunnel
{
    _Has_lock_level_(TunnelLockLevel) CRITICAL_SECTION cs;
};

struct Channel
{
    _Has_lock_level_(ChannelLockLevel) CRITICAL_SECTION cs;
};

void OrderInversion(Channel* pChannel, Tunnel* pTunnel)
{
    EnterCriticalSection(&pChannel->cs);
    // Warning C26105
    WaitForSingleObject(gMutex, INFINITE);
    EnterCriticalSection(&pTunnel->cs);
    LeaveCriticalSection(&pTunnel->cs);
    LeaveCriticalSection(&pChannel->cs);
}
```