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Re: MT and variables simple question [message #43202 is a reply to message #43201]

Fri, 06 June 2014 15:48

Didier is currently offline

Didier
Messages: 680
Registered: November 2008
Location: France

Contributor

Hello Koldo,

As i said Quote:

if you modify a variable using the var itself or a pointer to it: the result is the same ==> you have to protect the variable

So if data10 or vars[10] are accessed by several threads you have to put :

INTERLOCKED {
    data10 = &vars[10];
}

BUT ... you have to be careful which INTERLOCK method to use:

INTERLOCKED : uses local static mutex which only protects this code (and only this one) from being accessed by several threads at same time.
INTERLOCKED(mutex) : uses the parameter mutex which allows you to protect several parts of code by calling INTERLOCKED(mutex) each time

If you only wan't to protect variables, then you probably need to use INTERLOCKED(mutex) everywhere the variable is accessed.
Here is what I mean:

// If you need to protect data10
Mutex mtx;
..
..
// in code of first thread
INTERLOCKED(mtx) {
    data10 = &vars[10];
}
..
..
// somewhere in another thread's code
INTERLOCKED(mtx) {
    data10 = xxxxx;
}

Hope I am clear enough Confused

Confused

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[Message index]

		MT and variables simple question By: koldo on Thu, 05 June 2014 10:29
		Re: MT and variables simple question By: Didier on Thu, 05 June 2014 22:32
		Re: MT and variables simple question By: koldo on Fri, 06 June 2014 14:23
		Re: MT and variables simple question By: Didier on Fri, 06 June 2014 15:48
		Re: MT and variables simple question By: koldo on Sun, 08 June 2014 17:01
		Re: MT and variables simple question By: Didier on Mon, 09 June 2014 20:36
		Re: MT and variables simple question By: koldo on Tue, 10 June 2014 08:46
		Re: MT and variables simple question By: ManfredHerr on Tue, 10 June 2014 15:59
		Re: MT and variables simple question By: mirek on Wed, 11 June 2014 08:16
		Re: MT and variables simple question By: Didier on Thu, 12 June 2014 21:06
		Re: MT and variables simple question By: ManfredHerr on Thu, 12 June 2014 21:44
		Re: MT and variables simple question By: mirek on Mon, 16 June 2014 17:45

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