C++ - How to initialise an array of atomics?
std::array<std::atomic<std::size_t>, 100> A;
for(auto&x:A)
std::atomic_init(&x,std::size_t(0));
does the job using
clang++ -std=c++11 -stdlib=libc++ -Weverything -Wno-c++98-compat
using clang-3.3. I also tried with gcc 4.8
, but it doesn't support std::atomic_init()
. However, I suppose you can replace std::atomic_init(&x,std::size_t(0))
with x=std::size_t(0)
.
Note that std::atomic<>
is not copyable, which breaks some container methods (including construction of std::array<std::atomic<T>>
from a T
). Also, storing atomics in an array may cause false sharing, affecting performance.
EDIT 2019
The code in the accepted answer by Zac Howland does not compile (neither with clang nor with gcc). Here is a version that will
struct foo
{
std::array<std::atomic_size_t,2> arr= {{{0},{0}}};
std::atomic_size_t arr_alt[2] = {{0},{0}};
};