DVD write & read

I want to write xml file to DVD or CD.

i am using Linux platform, Qtcreator IDE.

I need API for read and write Functionality for DVD or CD.

Data from mounted CD/DVD media is read just like any other file.
Qt has no features related to writing optical media.

Low level CDDA or raw access to read the media and CD/DVD writing is done using direct access to SCSI generic devices on Linux. Look at the implementation in CdrDAO, CDRecord, or cdrkit in conjunction with mkisofs/growisofs.