std::move doe's not compile when moving an std::packaged_task<void()> object.
the errors are:
error C2182: '_Get_value' : illegal use of type 'void'
error C2182: '_Val' : illegal use of type 'void'
error C2182: '_Val' : illegal use of type 'void'
error C2665: 'std::forward': none of the 2 overloads could convert all the argument types
error C2512: 'std::_Promise': no appropriate default constructor available
The code is:
struct CalcFib
{
int m_num;
int m_res;
CalcFib(int number) :m_num(number)
{
}
CalcFib() :m_num(0)
{
}
void operator()()
{
m_res = fib(m_num);
}
int fib(int num)
{
if (num < 2) return num;
else return fib(num - 1) + fib(num - 2);
}
};
std::packaged_task<void()> task(std::move(CalcFib(30)));
std::packaged_task<void()> task1 = std::move(task);
This code is successfully compiled:
struct CalcFib
{
int m_num;
int m_res;
CalcFib(int number) :m_num(number)
{
}
CalcFib() :m_num(0)
{
}
int operator()()
{
m_res = fib(m_num);
return m_res;
}
int fib(int num)
{
if (num < 2) return num;
else return fib(num - 1) + fib(num - 2);
}
};
std::packaged_task<int()> task(std::move(CalcFib(30)));
std::packaged_task<int()> task1 = std::move(task);
