title: Max length of "tzname" field / timezone identifier name
body: <p>I am trying to find the max length of a timezone identifier. This is the string used as the timezone name (e.g. "America/New_York"). The tz database is not helpful; I could not find implementation details.</p>
  
  <p><a href="http://msdn.microsoft.com/en-us/library/system.timezoneinfo.id.aspx" rel="noreferrer">Microsoft (.NET Framework 4.5) suggests a max length of 32</a>, but this seems to be a limitation of their registry.</p>
  
  <p><a href="http://www.gnu.org/software/libc/manual/html_node/Minimums.html" rel="noreferrer">libc points to a limit called "_POSIX_TZNAME_MAX", which is 3 characters long</a>, but this is an absolute minimum requirement for POSIX compliance. Typically, I guess an implementation will use more.</p>
  
  <p>So the real question is: What's an acceptable string length to safely store timezone "tzname" / identifier name?</p>