Post date: Jul 12, 2011 3:41:30 AM
The files of WordPress define many useful PHP functions. Some of the functions, known as Template Tags, are defined especially for use in WordPress Themes. There are also some functions related to actions and filters (the Plugin API), which are therefore used primarily for developing Plugins. The rest are used to create the core WordPress functionality.
Many of the core WordPress functions are useful to Plugin and Theme developers. So, this article lists most of the core functions, excluding Template Tags. At the bottom of the page, there is a section listing other resources for finding information about WordPress functions. In addition to this information, the WordPress phpdoc site details all the WordPress functions by version since 2.6.1.
You can help make this page more complete!
Here are some things you can do to help:
Add documentation to un-documented functions, by creating sub-pages or at least by adding short comments in the lists below. If you create a subpage for a function, please include information and examples of usage of that function, if possible, per the examples found in Template Tags.
List more functions here, following the category structure.
Correct errors by moving functions to better categories where appropriate, and of course fixing typos. Note: that it is OK for a function to appear in more than one category.
Read Contributing to WordPress to find out more about how you can contribute to the effort!
Posts
is_post (deprecated)
Post insertion/removal
Pages
Custom field (postmeta)
Attachments
Bookmarks
Terms
Others
Categories
Category Creation
Tags
Taxonomy
is_taxonomy (deprecated)
is_term (deprecated)
Time/Date Functions
Serialization
Options
Admin Menu Functions
Form Helpers
Nonces and Referers (Security)
XMLRPC
Localization
Cron (Scheduling)
Conditional Tags Index
Miscellaneous
make_url_footnote (deprecated)
As of v3.0, WordPress includes WPMU functionality.
Old WPMU functions reference can be found at http://codex.wordpress.org/WPMU_Functions
(deprecated page).
Multisite administration Functions
These functions are found in file
wp-admin/includes/ms.php (since 3.0.0).
Multisite Functions
Site/blog functions that work with the blogs table and related data, found in file wp-includes/ms-blogs.php (since 3.0.0).
Defines constants and global variables that can be overridden, generally in wp-config.php, found in file wp-includes/ms-default-constants.php (since 3.0.0).
Multisite WordPress API, found in file
wp-includes/ms-functions.php (since 3.0.0).
These functions are needed to load Multisite,
found in file wp-includes/ms-load.php (since 3.0.0).