C CGI getting junk out of stdin

[Riley]

I'm using POST requests on my webforms and in my c code I parse out the variables, but there is the extra junk on the end that I don't want and don't know why it's sent. I use content length to find the length of the data. Why is the extra junk on the end and how do I get rid of it? (I tried using isalnum, but it doesn't filter out everything).

[Stuka]

Could you show an example of what's happening? If so, we might have a better idea of how to fix it....