What is the main difference between require and include in PHP?

The main difference between require and include in PHP lies in their behavior when the specified file cannot be found or fails to be included. When using require, if the specified file is not found, PHP will emit a fatal error and halt the execution of the script. This is particularly useful when the inclusion of the file is critical for the application to run, such as including important libraries or scripts that define essential functions or classes.

On the other hand, include will emit a warning if the file cannot be included, but it allows the script to continue executing. This means that even if the file is not found, the rest of the script will still run, which might lead to undesired behavior if the included file contained necessary code.

This distinction is crucial for developers to understand as they design their applications, ensuring that they use require in situations where the presence of a file is essential for the application’s operation, while include may be better suited for optional files.

The other statements do not accurately describe the fundamental difference between these two constructs. For example, require and include do not differ significantly in performance (the first choice does not capture the critical functional distinction). Similarly, the usage of require and include is not limited to specific types of files like templates or configuration