php includes

[john12kuk]

hi i was just wondering how php includes are handled. by this i mean

<?php require("header.php"); ?>

would the php in header.php be treated as if it replaced that line. for example if i was using sessions, would i need to do session_start in both header.php and the file it was included in, or would it be ok just to do it in header.php, taking in to account that i want to make use of session variables in scripts in both the files?

hope this makes sense

thanks in advance for the help

[planetsim]

A PHP include/require work similar except when it comes error handling.

Basically an include is just like programming what was ever in x.php when in b.php when we include x.php

x.php

 
<?php
$var = "Hello World";
?>

b.php

<?php
include 'x.php';
echo $var;
?>

That should print Hello World now all it looks like when PHP engine sees it is this

<?php
$var = "Hello World";
echo $var;
?>

Well not entirely true but if there is an include/require the code is placed into the code as if it was already there.

[rehfeld]

yeah like both you said, and the above poster, its pretty much like cutting and pasting the contents of into the parent file

the exceptions are:

php automatically drops out of php parsing mode as soon as it gets to the included code. thats why you must have valid <?php ?> tags in the included file as well

you can also use the return statment inside a file which has been included

the return statement acts just like in a function. php immediately stops parsing and returns to the script/code which called it origionally

<?php

$foo = true;

$fav_color = include('favcolor.php');

echo "the included file sais that its favorite color is: $fav_color";

?>

<?php
// favcolor.php


if ($foo) {
    return 'green';
} else {
    return 'red';
}

?>

[john12kuk]

cheers guys great help