Your OS doesn’t know about en_US.UTF-8. You didn’t mention a specific platform, but I can reproduce your problem: % uname -a OSF1 hunter2 V5.1 2650 alpha % perl -e exit perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LC_ALL = (unset), LANG = “en_US.UTF-8” are supported and installed on your … Read more
Run following commands It will solve this. Make sure to match the .UTF-8 part to the actual syntax found in the output of locale -a e.g. .utf8 on some systems.
I’m pretty sure “-” is the standard. If you see “_” somewhere it’s probably something some people came up with to make it a valid identifier. Personally I’d go with “-“, just to be correct. http://en.wikipedia.org/wiki/IETF_language_tag
The importance of locales is that your environment/os can provide formatting functionality for all installed locales even if you don’t know about them when you write your application. My Windows 7 system has 211 locales installed (listed below), so you wouldn’t likely write any custom code or translation specific to this many locales. Edit: The … Read more