mbeck

I have a situation where I need to alter 80 or so bytes of a binary file at the time an end user clicks on a link to download the file. The information that needs to be inserted includes such things as a timestamp and tracking ID. Space has already been made in the binary file for the insertion of the data, so there is no need to move anything around. The data needs to be inserted about 60 bytes into the file, not at the very start. The files themselves may be very large (gigs). Can anyone think of an efficient way to write the data to the file at the same time as the download? Thanks in advance, O.T.