C26130

  • Article

Note

This article applies to Visual Studio 2015. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

warning C26130: Missing annotation _Requires_lock_held_(<lock>) or _No_competing_thread_ at function <func>. Otherwise it could be a race condition. Variable <var> should be protected by lock <lock>.

Warning C26130 is issued when the analyzer detects a potential race condition but infers that the function is likely to be run in a single threaded mode, for example, when the function is in the initialization stage based on certain heuristics.

Example

In the following example, warning C26130 is generated because a _Guarded_by_ member is being modified without a lock.

  
typedef struct _DATA   
{  
    CRITICAL_SECTION cs;  
    _Guarded_by_(cs) int data;  
} DATA;  
  
void Init(DATA* p)   
{  
    p->data = 0; // Warning C26130  
}

Example

If the previous code is guaranteed to be operated in a single threaded mode, annotate the function by using _No_competing_thread_, as shown in the following example.

  
typedef struct _DATA   
{  
    CRITICAL_SECTION cs;  
    _Guarded_by_(cs) int data;  
} DATA;  
  
_No_competing_thread_ void Init(DATA* p)   
{  
    p->data = 0; // Warning C26130 will be resolved  
}

Example

Alternatively, you can annotate a code fragment by using _No_competing_thread_begin_ and _No_competing_thread_end_, as follows.

  
typedef struct _DATA   
{  
    CRITICAL_SECTION cs;  
    _Guarded_by_(cs) int data;  
} DATA;  
  
void Init(DATA* p)   
{  
    _No_competing_thread_begin_  
    p->data = 0; // Warning C26130 will be resolved  
    _No_competing_thread_end_  
}