What is output buffering and why is one using it in PHP?

I have a script that needs to submit to an iframe and get a return value. However, the coldfusion page i am submitting to needs to do additional processing that has nothing to do with the return value, so I want to return the value to the iframe and then redirect the iframe to about:blank before ...

I have inherited code using ReadFile Windows API method to read single byte from parallel port in a loop. The code passed CString instance as the buffer argument, and 1 as the number of bytes to read, something like this: CString inBuffer = ""; bResult = ReadFile(hCom, inBuffer.GetBuffer(1), 1, &...