Home/ Questions/Q 7197187
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-28T20:55:41+00:00

The C++11 standard includes the wonderful std::atomic<T> , which has member functions like this

  • 0

The C++11 standard includes the wonderful std::atomic<T>, which has member functions like this one:

integral fetch_add(integral, memory_order = memory_order_seq_cst);

However, it seems to be lacking in an add_fetch method. tbb::atomic<T> overloads the += operator to behave like add_and_fetch:

 value_type operator+=( D addend ) {
     return fetch_and_add(addend)+addend;
 }

Through empirical observation, std::atomic<T> behaves the same way, but I cannot find where it says so in the standard or if that is just my STL implementation. Is this behavior guaranteed by the standard?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    std::atomic<T> if T is an integral type, has a member operator+= which does the same thing. It is described, along with all other atomic compound assignment operators in §29.6.5/30-32

    C A::operator op=(M operand) volatile noexcept;

    C A::operator op=(M operand) noexcept;

    Effects: fetch_key(operand)

    Returns: fetch_key(operand) op operand

    • 0