How can class method access be safely controlled in a C++ mutli threaded program using boost?

Question

I want to translate some Java code into C++. One of the Java classes extends the Thread class and contains the following method:

 public static synchronized String createUniqueID() {
    //some code here
}

How can I synchronize (in the Java sense of the word) class methods in C++ using Boost? I have read about using boost::mutex for synchronizing access to shared data, but I am not sure how to apply this to C++ class methods.

Do you know what `synchronized` does? You just need to emulate the same thing with `boost::mutex`. — R. Martinho Fernandes, Nov 29 '11 at 17:09
I know about boost::mutex and i have used it for shared data. However, i dont know how can we use it for methods? can you help by providing an example code? — sufyan siddique, Nov 29 '11 at 17:11
Depending on the specifics, you might even be able to get away with some atomics. — Kerrek SB, Nov 29 '11 at 17:16
Lock at this: http://stackoverflow.com/questions/578904/how-do-synchronized-static-methods-work-in-java — ante, Nov 29 '11 at 17:17

score 4 · Accepted Answer · answered Nov 29 '11 at 17:19

4

The following is equivalent to a Java synchronized method in C++. In fact, it is exactly equivalent, with the obvious exceptions that it is written in a different language and a different threading library.

class Thing {
  public:
    static std::string createUniqueId () {
        boost::unique_lock<boost::mutex> synchronized(mutex_);
        // ... generate a unique id here.
    }

  protected:
    static boost::mutex mutex_;
};

Note that the mutex is protected, not private, allowing you to use the same mutex (as you should) in subclasses.

answered Nov 29 '11 at 17:19

Andres Jaan Tack

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Notice that the given method is `static`. – R. Martinho Fernandes Nov 29 '11 at 17:20
Totally. Thanks for the catch. – Andres Jaan Tack Nov 29 '11 at 17:23

score 0 · Answer 2 · answered Nov 29 '11 at 17:09

0

Use a static (i.e. class) mutex.

answered Nov 29 '11 at 17:09

Basile Starynkevitch

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score 0 · Answer 3 · answered Nov 29 '11 at 17:25

actually i do not understand what you said that "but I am not sure how to apply this to C++ class methods"

boost::mutex

you want to use, you must declare that. is not take effect now you must use

`boost::mutex::scoped_lock `

to effect it it can unlock automaticlly

How can class method access be safely controlled in a C++ mutli threaded program using boost?

3 Answers3