how to validate xml files against xsd

Hi,

  I am using libxml2 for my project and have few basic questions :

 

1.   How to validate xml files against xsd ?

 

2 . Where can i store version number for particular file (which also should match with xsd) ?

   ;   I tried exploring "attributes"; in xsd ,but the same is not getting reflected in .xml files ?

Kindly reply.
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Regards,
Suresh Chandak