i think what merlyn is trying to tell you is that you do it by rewriting the whole file... meaning, read it in, and write it back out with what you want in front of it.

seek, if i have it right, affects only whence you read, not whither you write.

(in other words, as some might say, "it can't be done" -- appending is inherently to the end of a file. sad, isn't it?)