Piping to process with c++
<p>I have finally worked out how to get stdin and stdout to pipe between the main app and a process created with CreateProcess (win32) or exec (linux).  Now I am interested in harnessing the piping nature of an app.  The app I am running can be piped into:</p>

<pre><code>eg: cat file.txt | grep "a"
</code></pre>

<p>If I want to run "grep", sending the contents of "file.txt" to it (which I have in a buffer in my c++ app), how do I do this?  I assume I don't just pump it down stdin, or am I wrong.  Is that what I do?</p>
