Top reasons not to use setlocale() for character encoding conversion

Many WordPress plugins use the setlocale() function.

While it’s generally safe to use setlocale() to get various information about a specific locale, it’s essential to understand that using setlocale() to perform string manipulations has significant disadvantages.

The goal of this article is to raise awareness about those disadvantages.


So, what are they?

  1. Firstly, setlocale() is not thread-safe. If you run WordPress on shared hosting, you may experience sudden changes in locale settings, as though your pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the Plugin Directory or can be cost-based plugin from a third-party never called setlocale().
  2. String functions that rely on setlocale() to detect the current locale don’t process some characters correctly, even if the correct locale is set with setlocale().

Take a look at this example.

The expected output of the script is Ž, but the actual output is Ů.


These are some recommendations on using setlocale() that could make using it safer:

  1. Don’t use setlocale() to process strings in different encodings unless absolutely unavoidable.
  2. Don’t use setlocale() with LC_ALL. Instead, specify the exact categoryCategory The 'category' taxonomy lets you group posts / content together that share a common bond. Categories are pre-defined and broad ranging. of functions you need (e.g., LC_MONETARY, LC_NUMERIC).
  3. If you need to change the current locale, you must change it back to the previous value in order to preserve thread-sanity. At this time, C should be used as the default locale setting.

#best-practices, #security