std :: to_string线程安全吗？

Question

I am looking to convert integer types to string using std::to_string , but I saw this paragraph:

std::to_string relies on std::locale for formatting purposes, and therefore concurrent calls to std::to_string from multiple threads may result in partial serialization of calls.

But I couldn't find anything else on this topic, Google didn't come up wit anything, as did MSDN. I am using Visual Studio 2013 if it matters.

Is this thread safe? If so, how?

Answer 1

std::to_string behaves as if it calls sprintf ( [string.conversions]/7 ), and the behavior of sprintf depends on the global locale, which can be modified by setlocale (or by std::locale::global , which internally calls setlocale ).

The wording in [clocale.syn]/2 seems to imply that std::to_string is thread safe, because it does not allow setlocale to introduce a data race with std::to_string or sprintf .