gztell() not working?

I'm working on a project which will involve storing text in a flat gzipped file and recording the position within that file of each text entry. However, gztell() doesn't seem to be working as it should. I open the flat file using gzopen($filename, "ab9"). Appending to the file works just fine; however, when the file is opened gztell() returns 0, and as the text is written returns offsets from that zero point. As I understood it, gztell() was supposed to return the offset into the uncompressed file stream. Anyone know what's going on? Stephen -- Stephen Granade | Interested in adventure games? sgranade@phy.duke.edu | Visit About Interactive Fiction Duke University, Physics Dept | http://interactfiction.about.com