Difference Between Include_once() and require_once

[Lakshmi]

HIWhat Is the Difference Between Include_once() and require_once()?Give me the breif Description..

[Jack McKalling]

include() and require() are practically the same.There is only one difference, require() pastes the content and executes it, while include() only pastes, and executes if the calling script asks for it.For example:

$var = 1;if ($var == 2){ include_once("file.inc"); require_once("file2.inc"); }

In this code, only file2.inc will be inserted Because the condition is false, include() won't be executed, where require() will :)the _once() addition only tells the script should only insert the content once, and skip the next calling to that file when there is another call

[Bjørnar]

The difference is that require_once will produce a fatal error on failure, while include only produces a warning.

[vijay]

Hi, Or Refer Site"http://us2.php.net/manual/en/function.require-once.php"require_once()The require_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the require() statement, with the only difference being that if the code from a file has already been included, it will not be included again. See the documentation for require() for more information on how this statement works. require_once() should be used in cases where the same file might be included and evaluated more than once during a particular execution of a script, and you want to be sure that it is included exactly once to avoid problems with function redefinitions, variable value reassignments, etc. For examples on using require_once() and include_once(), look at the PEAR code included in the latest PHP source code distributions. Vijay