Is it better to use require_once('filename.php') or require_once 'filename.php';

Is this just a stylistic difference, or does using 开发者_Python百科require_once('filename.php') vs require_once 'filename.php' have actual load/efficiency differences?

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Pear Coding Standards say :

"include_once and require_once are statements, not functions. Parentheses should not surround the subject filename."

Source : http://pear.php.net/manual/en/standards.including.php

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It's exactly the same thing. It's a matter of style.

The parentheses may get in the way some times. For instance, this example from the manual doesn't do what you expect:

if (include('vars.php') == 'OK') {
    echo 'OK';
}

See example #4.

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What does your heart tell you?

Performance difference, if any: negligible.

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There is no difference. I don't use the brackets 'cause they are not necessary. require_once is no function.

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include, include_once, require and require_once are not functions, they are statements, that is why you should not use ().

Also, consider this from php.net:

<?php

// won't work
if (include('vars.php') == TRUE) {
    echo 'OK';
}

// works
if ((include 'vars.php') == TRUE) {
    echo 'OK';
}

?>