Request For NullMutex Feature

[ksgokul]

Hi,
Lot of times, when we do template meta programming, we need to provide some containers with no mutex( tbb containers ) and some containers with a tbb Mutex (Boost /std containers). The Scoped Lock feature makes the code different for both. If we can have a NullMutex feature like the one available in ACE( ACE_Null_Mutex), it would be easy to handle such situations. Please advise me on any work arounds currently available.This NullMutex is more like a no-op.

Thanks in advance,
Gokul.

[Alexey-Kukanov · Accepted solution]

If you only use scoped lock pattern (i.e. no explicit calls to acquire/release), the following should work:

[cpp]class null_mutex {
    //! Deny assignment and copy construction
    null_mutex( const null_mutex& );
    void operator=( const null_mutex& );
public:
    class scoped_lock {
    public:
        scoped_lock( null_mutex& ) {}
        ~scoped_lock() { }
    };

    // Mutex traits
    static const bool is_rw_mutex = false;
    static const bool is_recursive_mutex = false;
    static const bool is_fair_mutex = false;
};
[/cpp]

Anyway the idea is reasonable. Thanks for the suggestion.

[ksgokul]

Quoting - Alexey Kukanov (Intel)

If you only use scoped lock pattern (i.e. no explicit calls to acquire/release), the following should work:

[cpp]class null_mutex {
    //! Deny assignment and copy construction
    null_mutex( const null_mutex& );
    void operator=( const null_mutex& );
public:
    class scoped_lock {
    public:
        scoped_lock( null_mutex& ) {}
        ~scoped_lock() { }
    };

    // Mutex traits
    static const bool is_rw_mutex = false;
    static const bool is_recursive_mutex = false;
    static const bool is_fair_mutex = false;
};
[/cpp]

Anyway the idea is reasonable. Thanks for the suggestion.

Thanks for the Solution..

Gokul.

[Alexey-Kukanov]

We willmake an extended version of it part of TBB.

Also during the internal discussion, it was suggested that is_recursive and is_fair traits should be true for null_mutex.

[ksgokul]

Quoting - Alexey Kukanov (Intel)

We willmake an extended version of it part of TBB.

Also during the internal discussion, it was suggested that is_recursive and is_fair traits should be true for null_mutex.

Great to hear that the request has been accepted. I will update the static variables accordingly. Actually the new values make a lot of sense.