QtConncurrent - calling function within the class

Hello everyone.

I need to call a function from another function in the same class. As it requires much time to be finished (running mysql query on external server), I want it to be in another thread. My code is sth like that:

Code:

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void runQuery(){
    ...
}
 
void getProducts(){
    QtConcurrent::run(runQuery);
}

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I get an error:

Code:

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no matching function to call to 'run(<unknown type>)'

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Could you help me out please?

Look into QThread, not QtConcurrent.

Quote:

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Originally Posted by mgoetz

Look into QThread, not QtConcurrent.

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Still don't know how to use it in my class. I will appreciate some tips and hints.

Code:

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#include <boost/bind.hpp>
 
void YourClassName::getProducts(){
    QtConcurrent::run( boost::bind(&YourClassName:runQuery, this) );
}

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obviously, you need to take care that runQuery() and your class are "thread safe" because they will run concurrently...

For details on Boost and Boost.Bind see www.boost.org

HTH

Quote:

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Originally Posted by caduel

Code:

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#include <boost/bind.hpp>
 
void YourClassName::getProducts(){
    QtConcurrent::run( boost::bind(&YourClassName:runQuery, this) );
}

---

obviously, you need to take care that runQuery() and your class are "thread safe" because they will run concurrently...

For details on Boost and Boost.Bind see www.boost.org

HTH

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Thanks for input, but the solution isn't working. It compiles without errors and warnings, program works, but not properly. It doesn't get results from a database. Isn't a new instance of my class being created by QtConcurrent::run( boost::bind(&YourClassName:runQuery, this) );? What can be the couse?

no, boost::bind creates a function object by binding (here runQuery()) a member function to an object (here this). So it exeutes runQuery() on the very object you call getProducs() on.

You can also pass YourClassName() instead of this, then you create a temporary that is used for executing. (Also note that you might need a separe db connection if you are using the db from the main thread, too.)