Write Pcm data in a loop but it does not play

Hi all,
I'm new to this forum, expecting your sincere help.
I have  ported an application on SDK 2.0. Application try to write data in a loop regularly, but due to asynchronous implementation it does not while writing data through update buffer, when it goes back to frame then it play  last written data.

Is there any way to write data in a loop and it should play regularly while control is in application.
as
 while(1)
   {
    WriteL(buffer);
       // but it is not playing once it goes out of loop and back to frame then it plays last data.
    }

what API needs to be called to play in loop .

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chandrasheklhar