pwnna

I have a Fujifilm camera and decent lens that can do 600mm FF equiv is not cheap. I'm wondering what is the best option for bird photography at that range? There are some tiny 1/2.3 compact cameras like the Sony hx99 that doesn't seem too good. There also seem to be an option of picking up a m43 camera with a 300mm (600mm equivalent) lens. What is everyone's favorite options?

I have this code where I have a class MyElement that holds a MyData<UnderlyingData> that's constructed during the constructor:

#include <atomic>
#include <iostream>
#include <vector>

struct UnderlyingData {
  int a;
  int b;

  UnderlyingData(int _a, int _b) : a(_a), b(_b) {}
};

template <typename T> class MyData {
public:
  std::atomic<T> data_;

  template <typename... Args>
  MyData(Args &&...args) : data_(T(std::forward<Args>(args)...)) {}
};

class MyElement {
public:
  int c;
  MyData<UnderlyingData> mydata;

  explicit MyElement(int _c) : c(_c), mydata(0, 6) {}
};

int main() {
  std::vector<MyElement> arr;
  arr.emplace_back(5);

  std::cout << arr.at(0).c << " " << arr.at(0).mydata.data_.load().a << " "
            << arr.at(0).mydata.data_.load().b << "\n";

  return 0;
}

As you can see, MyData<UnderlyingData> holds an atomic<UnderlyingData> and the constructor of MyData attempts to perfect forward to the UnderlyingData through the atomic. This code works if I try to construct a MyData<UnderlyingData> variable manually, or a MyElement variable, like this:

  MyElement element(5);
  std::cout << element.c << " " << element.mydata.data_.load().b << "\n";

However, when I put MyElement into a vector and use either emplace_back or push_back(MyElement(5)), I get this cryptic error:

test.cpp: In instantiation of ‘MyData<T>::MyData(Args&& ...) [with Args = {MyData<UnderlyingData>}; T = UnderlyingData]’:
test.cpp:20:7:   required from ‘void std::_Construct(_Tp*, _Args&& ...) [with _Tp = MyElement; _Args = {MyElement}]’
/usr/include/c++/11/bits/stl_uninitialized.h:92:18:   required from ‘static _ForwardIterator std::__uninitialized_copy<_TrivialValueTypes>::__uninit_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = std::move_iterator<MyElement*>; _ForwardIterator = MyElement*; bool _TrivialValueTypes = false]’
/usr/include/c++/11/bits/stl_uninitialized.h:151:15:   required from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = std::move_iterator<MyElement*>; _ForwardIterator = MyElement*]’
/usr/include/c++/11/bits/stl_uninitialized.h:333:37:   required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = std::move_iterator<MyElement*>; _ForwardIterator = MyElement*; _Tp = MyElement]’
/usr/include/c++/11/bits/stl_uninitialized.h:355:2:   required from ‘_ForwardIterator std::__uninitialized_move_if_noexcept_a(_InputIterator, _InputIterator, _ForwardIterator, _Allocator&) [with _InputIterator = MyElement*; _ForwardIterator = MyElement*; _Allocator = std::allocator<MyElement>]’
/usr/include/c++/11/bits/vector.tcc:474:3:   required from ‘void std::vector<_Tp, _Alloc>::_M_realloc_insert(std::vector<_Tp, _Alloc>::iterator, _Args&& ...) [with _Args = {int}; _Tp = MyElement; _Alloc = std::allocator<MyElement>; std::vector<_Tp, _Alloc>::iterator = std::vector<MyElement>::iterator]’
/usr/include/c++/11/bits/vector.tcc:121:21:   required from ‘std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::emplace_back(_Args&& ...) [with _Args = {int}; _Tp = MyElement; _Alloc = std::allocator<MyElement>; std::vector<_Tp, _Alloc>::reference = MyElement&]’
test.cpp:30:19:   required from here
test.cpp:17:34: error: no matching function for call to ‘UnderlyingData::UnderlyingData(MyData<UnderlyingData>)’
   17 |   MyData(Args &&...args) : data_(T(std::forward<Args>(args)...)) {}
      |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test.cpp:9:3: note: candidate: ‘UnderlyingData::UnderlyingData(int, int)’
    9 |   UnderlyingData(int _a, int _b) : a(_a), b(_b) {}
      |   ^~~~~~~~~~~~~~
test.cpp:9:3: note:   candidate expects 2 arguments, 1 provided
test.cpp:5:8: note: candidate: ‘constexpr UnderlyingData::UnderlyingData(const UnderlyingData&)’
    5 | struct UnderlyingData {
      |        ^~~~~~~~~~~~~~
test.cpp:5:8: note:   no known conversion for argument 1 from ‘MyData<UnderlyingData>’ to ‘const UnderlyingData&’
test.cpp:5:8: note: candidate: ‘constexpr UnderlyingData::UnderlyingData(UnderlyingData&&)’
test.cpp:5:8: note:   no known conversion for argument 1 from ‘MyData<UnderlyingData>’ to ‘UnderlyingData&&’

I've tried a number of permutations and can't seem to figure it out either. I don't understand why the constructor inferred seems to be UnderlyingData::UnderlyingData(MyData<UnderlyingData>) as I'm just passing two numbers to it... Any advice I can get is much appreciated.

I recently bought a refurbished x390. Got it and found the battery had one charge cycle on it. i5-8365U, 16GB of RAM, 256GB SSD, 1920x1080 IPS. A very nice machine as a backup to the family travel x1 nano.

I see a post here: https://lemmy.ca/post/921003. There is only one comment from me, but on lemmy.ml there are more comments and votes. Why is this the case?