Procedural Coding Method
By default, all variables, functions and classes are defined in the global namespace, which means that it is possible for your plugin to override variables, functions and classes set by another plugin and vice-versa. Variables that are defined inside of functions or classes are not affected by this.
Prefix Everything
All globally accessible code should be prefixed with a unique identifier. Prefixes prevent conflicts with other plugins and prevents them from overwriting your variables and accidentally calling your functions and classes.
In order to prevent conflicts with other plugins, your prefix should be at least 4 letters long, though we recommend 5. You should avoid using a common English word, and instead choose something unique to your plugin. We host tens of thousands of plugins on WordPress.org alone. There are hundreds of thousands more outside our servers. You’re going to run into conflicts.
A good way to do this is with a prefix. For example, if your plugin is called “Easy Custom Post Types” then you could use names like these:
