Hi all, I have found some problems (and possible solutions) concerning use of the gettext extension on multithreaded servers.
Usually gettext determines the locale to use for translations from one of the following environment variables: LC_MESSAGES, LANG, LANGUAGE, LC_ALL. These environment variables are usually set with calls to setlocale(). In multithreaded server environments, such as IIS on win32, this setup works fine IF you only want to use a single locale across all php requests. All threads/request call setlocale() with the same locale. However a typical reason to internationalize a php web application is to allow users to choose their own locale. Currently gettext on a multithreaded server will not support this scenario. As each thread calls setlocale() they will be setting the current locale for ALL threads. A solution on win32 is to use the thread-aware NLS win32 API [1]. The current win32 build of gettext (libintl-1.dll) will call GetThreadLocale() to determine locale if none of the environment variables listed above are set. For this to work though, SetThreadLocale() must be called previously. My first thought was that the win32 implementation of php setlocale() should call SetThreadLocale() instead. The benefit of this option would be transparency to the user. But I don't like this option since it mixes the old NLS API with the new one. Also setlocale() by definition sets the environment variables, which will cause gettext to never call GetThreadLocale(). The alternative then is to call SetThreadLocale() through a new php extension. I think this should be seperate from the gettext extension since locales are used more widely than just gettext. My current idea is to create an extension named w32nls. This would be a win32 only extension that would provide access to a collection of the functions in the win32 NLS API [1] including Get/SetThreadLocale(). Other usful functions include replacements for php functions that are dependent on any of the LC_* environment variables. These functions would suffer from the same problems as gettext in a multithreaded environment where each thread sets different locales. For example the strftime() function relies on the LC_TIME environment variable. The alternative functions, GetDateFormat() and GetTimeFormat(), could be provided in the w32nls extension. The downside however will be increased incompatibility between win32 and unix based PHP applications if such an extension is ever widely used. I welcome any feedback on these ideas before I proceed. Thanks, Nathan [1] http://msdn.microsoft.com/library/default.asp?url=/library/en-us/intl/nls_52 lh.asp -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
