The IO manager default architecture

Having solved the mystery of X keysym, keycode,and string (Xwindows needs to present a character as a string because some keys generate multi character sequences).  That was te last urdle, we know the default io mnager.

The caller obtains a connection from xchars, then calls io manager which forks and wait for message.    Basic IO manager tracks the current rectangle with keystrokes, and calls xchars outstr which does the rectangle rendering and folding. In default, the io manager does left, right,up and down keys. As well as backspace, and echos.  Caller may obtain a different rectangle for the current window, causing echo to be moved.

I consider this a snippet, there is not much here, rudimentary command  history,no argument macros. It likely will not do the number pad.  Cursors flat fill,  no color. Don't like it?  Load a better one. But the default io manager is important, it defines what should work on start up, something very fundamental in complexity management. You can always ask," Does it come up and accept commands manually", and that result, yes or no, clears much confusion and always guarantees a restart, when yes.