title: What happens if stdin fills up?
body: <p>This seems like a simple question, but I have had a really hard time finding an answer. I am writing a program in C where this seems possible (though remotely so) on some systems, as it appears there are situations where stdin has a buffer of only 4k.</p>
  
  <p>So, my question is, is there a standard way an OS deals with stdin filling up (i.e., a de facto standard, a posix requirement, etc)? How predictable is the outcome, if there is in fact some sort of standard way to deal with the situation?</p>