How do you create optional arguments in php?

The default value of the argument must be a constant expression. It can't be a variable or a function call.

If you need this functionality however:

function foo($foo, $bar = false)
{
    if(!$bar)
    {
        $bar = $foo;
    }
}

Assuming $bar isn't expected to be a boolean of course.

Much like the manual, use an equals (=) sign in your definition of the parameters:

function dosomething($var1, $var2, $var3 = 'somevalue'){
    // Rest of function here...
}

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