I create a QFuture that I want to use to parallelize calls to a member function. More precisely, I have a class solveParallel with .h :
class solverParallel {
public:
solverParallelData(Manager* mgr_);
virtual ~solverParallel(void);
void runCompute(solveModel * model_);
bool resultComput();
private:
Manager *myMgr;
QFuture<bool> myFutureCompute;
};
where the methode runCompute() is creating the myFutureCompute member. .cpp looks like
solveParallel::solveParallel(Manager* mgr_)
:m_mgr(mgr_)
{
}
solverParallel::~solverParallel(void){}
void solverParallel::runCompute(solveModel* model)
{
futureComput = QtConcurrent::run(&this->myMgr,&Manager::compute(model));
}
bool solverParallelData::resultComput()
{
return m_futureComput.result();
}
Include(s) are all right. Compilation fails, on line
futureComput = QtConcurrent::run(&this->myMgr,&Manager::compute(model));
with this error:
Error 44 error C2784: 'QFuture<T> QtConcurrent::run(T (__cdecl *)(Param1),const Arg1 &)' : could not deduce template argument for 'T (__cdecl *) (Param1)' from 'Manager **' solverparallel.cpp 31
In addition, on mouse info for '&Manager' in same line of code stands: Error: a nonstatic member reference must be relative to a specific object.
Do you see where is the trick? Thanks and regards.
QtConcurrent::run () also accepts pointers to member functions. The first argument must be either a const reference or a pointer to an instance of the class. Passing by const reference is useful when calling const member functions; passing by pointer is useful for calling non-const member functions that modify the instance.
Note that the QFuture::result () function blocks and waits for the result to become available. Use QFutureWatcher to get notification when the function has finished execution and the result is available. QtConcurrent::run () also accepts pointers to member functions.
In basic mode, the function passed to QtConcurrent::run () is able to report merely a single computation result to its caller.
Note that QtConcurrent::run does not support calling overloaded functions directly. For example, the code below won't compile: void foo(int arg) ; void foo(int arg1, int arg2) ; ...
From the official documentation :
QtConcurrent::run() also accepts pointers to member functions. The first argument must be either a const reference or a pointer to an instance of the class. Passing by const reference is useful when calling const member functions; passing by pointer is useful for calling non-const member functions that modify the instance.
You are passing a pointer to a pointer. Also notice that you cannot pass the arguments the way you do, but as extra arguments in the run
function. The following should work:
futureComput = QtConcurrent::run(this->myMgr,&Manager::compute, model);
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