I don't really have my head around the Boost IO filter architecture yet, but I have managed to get a very basic filter working.  I'm having some trouble with end-of-input issues.  I think what I'm trying to do comes up frequently, so hopefully this will be a straightforward answer...
<br><br>What I'm trying to do is write a filter that takes in input one character at a time (for simplicity -- for now), and outputs encrypted characters.&nbsp; The block size is 4 bytes, so every 4 characters I can encrypt, and then spit out the result.&nbsp; If I hit the end of input, then I want to pad the plaintext, encrypt and output the final block.&nbsp; My trouble is knowing when the end-of-input has arrived.&nbsp; Is there a well defined way that my output filter is notified of a close event or something similar?&nbsp; I did see close functions defined in the example filters, but mine isn't getting called.&nbsp; I tried to look at the base64 encode/decode headers (which would have to deal with the same issue) but I couldn't really follow it.
<br><br>Any help is appreciated. <br><br>Thanks<br><br>-Steve<br>