Locale-specific integer formatting doesn't work on iOS

[olliwang]

Hi, I was trying to print pretty integer on iOS. However, it seems std::setlocale() is not allowed in iOS (http://stackoverflow.com/questions/32594377/setlocale-works-in-ios-simulator-but-fails-on-device). Is it possible to provide other way to achieve this in iOS? Thanks.

[vitaut]

The library doesn't use setlocale. Could you post the code and an error that you get on iOS?

[olliwang]

I tried the following code as described in #305

std::setlocale(LC_ALL, "en_US.utf8");
fmt::print("cppformat: {:n}\n", 1234567);

However, the first line always returns NULL and the commas never printed.

[vitaut]

I see. Since iOS doesn't seem to support locales, I guess you can provide your own imlementation of fmt::std::localeconv as it is done in format-test, something like:

namespace fmt {
namespace std {
lconv *localeconv() {
  static lconv lc = {...}; // initialize thousands_sep here
  return &lc;
}
}
}

[olliwang]

Thanks @vitaut. This approach seems a bit tricky. Writing a custom function to add separators would be easier for me. However, it would be great if fmt can support iOS out-of-box.