need help in understanding gist function

I need help in understanding certain things in gist ...<br />1. What is the functionality of gistplacetopage() function
ingist.c ?Can you please give me detail description of this function.<br />2. I have left and right buffers with values
thatI have filled. Now, how do I write these changes(buffers) permanently into gistentry pages? <br /><br />Thanks<br
/>Sharat<br/>