global initialization order with constexpr

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Let's consider this hunk of code that simply tries to initialize a map from a constexpr array:

#include <string>
#include <map>
#include <array>
#include <tuple>

constexpr std::array<std::pair<int, const char *>, 10> my_array {
    { { 0, "dd" },
    { 1, "dd" },
    { 2, "dd" },
    { 7, "dd" },
    { 8, "dd" },
    { 9, "dd" }}
   };

std::map<int, std::string> my_map(std::begin(my_array), std::end(my_array));

int main() {
    return my_map[0].size(); //dummy random operation
}

I know there is not way to predict initialization order for the two variables (my_array and my_map). That said, my_array is constexpr, thus should be available a compile time, thus there should be no "initialization order" problem at startup.

Is this code correct or does the initialization order problem remains?

constexpr c++14 c++
1 Answers

[basic.start.static/2]:

Constant initialization is performed if a variable or temporary object with static or thread storage duration is constant-initialized. [...] Together, zero-initialization and constant initialization are called static initialization; all other initialization is dynamic initialization. All static initialization strongly happens before ([intro.races]) any dynamic initialization.

So, "Is this code correct?": Yes, as my_array is constant initialized, and this happens before dynamic initialization (my_map).

(This quote is from the current draft standard, but this rule exists for C++14 as well)

user_81571870
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