Description:
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A class that extends pdo uses a persistant mysql-connection.
Different objects of this class are constructed, but as soon as a reference on one of these objects is reused, all of the objects that exist at this moment loose their attributes.
Objects created after this procedure have their attributes.

Tested with php 5.9 and 5.18

Test script:
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$o1 = new mysqlPDO('test_db', 'mydbserver.hds', 'root', '');
$o2 = new mysqlPDO('test_db', 'mydbserver.hds', 'root', '');
$o3 = new mysqlPDO('test_db', 'mydbserver.hds', 'root', '');
echo 'o1: '.$o1->attr.'<br>';
echo 'o2: '.$o2->attr.'<br>';
echo 'o3: '.$o3->attr.'<br>';
$o2 = new mysqlPDO('test_db', 'mydbserver.hds', 'root', '');//At this point, o1-o3 loose their attributes
echo 'o1: '.$o1->attr.'<br>';
echo 'o2: '.$o2->attr.'<br>';
echo 'o3: '.$o3->attr.'<br>';
$o4 = new mysqlPDO('test_db', 'mydbserver.hds', 'root', '');//This one has attributes again
echo 'o4: '.$o4->attr.'<br>';

Expected result:
----------------
o1: abc
o2: abc
o3: abc
o1: abc
o2: abc
o3: abc
o4: abc

Actual result:
--------------
o1: abc
o2: abc
o3: abc
o1:
o2:
o3:
o4: abc