How does PDO::FETCH_CLASS populate the object properties before the constructor is called?

How does PDO::FETCH_CLASS populate the object properties before the
constructor is called?

References

Reference NO 1

http://stackoverflow.com/questions/15199359/how-does-pdofetch-class-populate-the-object-properties-before-the-constructor

Reference NO 2

http://stackoverflow.com/questions/8898794/using-pdofetch-class-with-magic-methods

Reference NO 3

http://php.net/manual/en/pdostatement.setfetchmode.php

Reference NO 4

http://php.net/manual/en/pdostatement.fetchall.php

Reference NO 5

http://net.tutsplus.com/tutorials/php/why-you-should-be-using-phps-pdo-for-database-access/

Reference NO 6

http://www.dreamincode.net/forums/topic/214733-introduction-to-pdo/

Reference NO 7

http://marc.info/?l=php-internals&m=122268112516864

Reference NO 8

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