Problems with PHP namespaces and built-in classes, how to fix?

Question

I'm writing a small library in PHP and i'm having some problems with built-in classes not being read. For example:

namespace Woody;

class Test {
  public function __construct() {
    $db = new PDO(params);
  }
}

This gives me:

PHP Fatal error: Class 'Woody\PDO' not found in /var/www/test.php

This is probably the same: [How to use “root” namespace of php?](http://stackoverflow.com/questions/6593621/how-to-use-root-namespace-of-php/6593676) — hakre, Aug 01 '11 at 16:35

hakre · Answer 1 · 2011-08-01T16:39:38.770

38

This:

namespace Woody;
use PDO;

Or:

$db = new \PDO(params);

Point in case is, that the class PDO is not a full qualified name within your Namespace, so PHP would look for Woody\PDO which is not available.

See Name resolution rules^Docs for a detailed description how class names are resolved to a Fully qualified name.

edited Aug 01 '11 at 16:39

answered Aug 01 '11 at 16:21

hakre

thanks for a better answer than my own. I knew the solution, but I didn't explain it nearly as well as you did! – Steve Hill Aug 02 '11 at 11:40
The `\PDO` method doesn't work for me in `PHP 5.5.12`, but this does: `use PDO;`. – Jo Smo Jul 05 '14 at 15:45
2

@tastro: I think as well that using `use` is good practice. Then you can see at the top of the file which classes are taken in. – hakre Jul 06 '14 at 14:52

ain · Answer 2 · 2011-08-01T16:29:44.503

6

Add a backslash before class name, ie

$db = new \PDO(params);

edited Aug 01 '11 at 16:29

answered Aug 01 '11 at 16:21

ain

score 3 · Answer 3 · answered Aug 01 '11 at 16:22

3

The below should work:

namespace Woody;

class Test {
    public function __construct() {
        $db = new \PDO(params);
    }
}

You need to prefix PDO with the backslash so PHP knows it's in the global namespace.

answered Aug 01 '11 at 16:22

Steve Hill

3 Answers3