Deprecate setlocale?

Hi, I'd like to get people's feedback for the idea of making setlocale be either deprecated and to be removed eventually or just increasing the warning level against people using it. The short version of why we should do this is that setlocale breaks things. It is a process wide operation, that is not thread safe on most platforms. Although people use it to alter the way strings are output, it also breaks libraries that are assuming that they are running in a "C" locale. https://bugs.php.net/bug.php?id=59571 - breaks Imagick https://bugs.php.net/bug.php?id=54538 - breaks NumberFormatter https://bugs.php.net/bug.php?id=66108 - breaks constants https://bugs.php.net/bug.php?id=67127 - breaks DateTime https://bugs.php.net/bug.php?id=69348 - breaks MySQL And there are quite a few other bug reports where setlocale is doing exactly what it is meant to do, but the unexpected side-effects are catching people out. We have libraries that ship with PHP for formatting dates, numbers etc that actually work, and don't break other libraries. So two questions: i) Are there any reasons why we couldn't or shouldn't plan for removing setlocale at some point in the future? i.e. does it do something that isn't supported by other libraries in PHP? ii) If it's not possible (or desirable) to remove it, how could we increase the warning level against using it? cheers Dan