Is there a boost function for parallel_for in C++?

Question

I need to do a parallel_for. Is there an easy implementation of this available in the standard C++ library, or in Boost? I have not found it.

By the way I am using Ubuntu. So I don't want Microsoft libraries.

Answer 1

Since C++17 we have most algorithm as potentially parallel versions using the "execution policy" argument: https://en.cppreference.com/w/cpp/algorithm/execution_policy_tag_t

For a simple for-each, the algorithm would befor_each: https://en.cppreference.com/w/cpp/algorithm/for_each

std::vector<int> v = get_tons_of_values();
std::for_each(std::execution::par, std::begin(v), std::end(v), [](int i) {
   work(i);
});

In this example, we "ask" the lambda to be executed in parallel.

Note that the algorithm will decide itself it it will effectively run in parallel and how to run in parallel. For example if there is not enough values to make the cost of running parallel worth it, it will not run in parallel on most implementations. Consult your standard library implementation documentation to learn about the heuristics they will use.