Only variables can be passed by reference

Question

I had the bright idea of using a custom error handler which led me down a rabbit hole.

Following code gives (with and without custom error handler): Fatal er

Answer 1

array_pop() tries to change that value which is passed as parameter. Now in your second example this is the return value from array_slice(). In engine terms this is a "temporary value" and such a value can't be passed by references. what you need is a temporary variable:

function foo(){
    $a=explode( '/' , 'a/b/c');
    $b=array_slice($a,-2,1);
    $c=array_pop($b);
    return $c;
}
print_r(foo());

Then a reference to $b can be passed to array_pop(). See http://php.net/references for more details on references.

Answer 2

Try this:

function foo(){
    $a = array("a","b","c");
    $b = array_pop($a);
    return $b;
}

Answer 3

Same question Strict Standards: Only variables should be passed by reference, also https://bugs.php.net/bug.php?id=48937.

Answer 4

I just got this error chaining methods.

doSomething()->andThis()

I had:

doSomething()-andThis() // missing `>` character

My scenario was a little more complex, but it stemmed from the accidental subtraction operation.

Answer 5

It's a memory corruption issue (according to PHP dev team). Just throw in an assignment:

function foo(){
    $b = array_pop($arr = array("a","b","c"));
    return $b;
}
print_r(foo());

:

function foo(){
    $a = explode( '/' , 'a/b/c');
    $c = array_pop($arr = array_slice($a,-2,1));
    return $c;
}
print_r(foo());

The second produces an E_STRICT. You can handle that differently in your error handler if you wish (if you don't want to change those functions).

Answer 6

array_pop() changes that value passed to it which is where the error is coming from. A function cannot be changed. In other words, you need to assign the array to a variable first (ref: manual), and then run array_pop().

The code you need is this:

function foo(){
    $a = array("a","b","c");
    $b = array_pop($a);
    return $b;
}

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Edit: Both functions you mentioned have the same problem. Assign the array to a variable and pass the variable to array_pop().