Difference between require, include, require_once and include_once?

php include require require-once
Scott B picture Scott B · Mar 10, 2010 · Viewed 601.2k times · Source

In PHP:

  • When should I use require vs. include?
  • When should I use require_once vs. include_once?

Answer

Leo picture Leo · Mar 10, 2010

There are require and include_once as well.

So your question should be...

  1. When should I use require vs. include?
  2. When should I use require_once vs. require

The answer to 1 is described here.

The require() function is identical to include(), except that it handles errors differently. If an error occurs, the include() function generates a warning, but the script will continue execution. The require() generates a fatal error, and the script will stop.

The answer to 2 can be found here.

The require_once() statement is identical to require() except PHP will check if the file has already been included, and if so, not include (require) it again.

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