CODEWITHSUNDEEP
c++multithreading
Zekria Ali
Zekria Ali

Reputation: 25

C++ Making a thread and passing Object by reference

Currently trying to pass an object by reference to another thread but I get errors when I try to build my solution.

void OrderServer(Orders& customerOrders)
{
    Item tempItem;
    customerOrders.add(tempItem);
}

int main()
{
Orders customerOrders();
auto serverThread = std::thread(OrderServer, std::cref(customerOrders));
serverThread.detach();
return 0;
}

The following is the error:

c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.11.25503\include\thr\xthread(240): error C2672: 'std::invoke': no matching overloaded function found 1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.11.25503\include\thr\xthread(248): note: see reference to function template instantiation 'void std::_LaunchPad<_Target>::_Execute<0,1>(std::tuple> &,std::integer_sequence<_Ty,0,1>)' being compiled

Upvotes: 0

Views: 553

Answers (2)

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

You could try simply:

auto serverThread = std::thread(OrderServer, customerOrders);

(and as told by François Moisan you have a typo when declaring customerOrders).

without any std::cref. However, your thread is later detached, but the customerOrders is destroyed by the return of main. That is probably an undefined behavior since OrderServer then works with a reference to some object which does not exist anymore.

Upvotes: 0

Fran&#231;ois Moisan
Fran&#231;ois Moisan

Reputation: 790

Orders customerOrders(); declares a function. This is known as the most-vexing parse.

You can simply use Orders customerOrders;

Upvotes: 2

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