wine/documentation/console

Console - First Pass
--------------------

Consoles are just xterms created with the -Sxxn switch.
A pty is opened and the master goes to the xterm side
and the slave is held by the wine side.  The console
itself it turned into a few HANDLE32s and is set 
to the STD_*_HANDLES.

It is possible to use the WriteFile and ReadFile commands
to write to a win32 console.  To accomplish this, all K32OBJs 
that support I/O have a read and write function pointer.
So, WriteFile calls K32OBJ_WriteFile which calls the K32OBJ's
write function pointer, which then finally calls write.

[this paragraph is now out of date]
If the command line console is to be inheirited or
a process inherits it's parents console (-- can that happen???),
the console is created at process init time via PROCESS_InheritConsole.
The 0, 1, and 2 file descriptors are duped to be the
STD_*_HANDLES in this case.  Also in this case a flag is set
to indicate that the console comes from the parent process or
command line.

If a process doesn't have a console at all, it's 
pdb->console is set to NULL.  This helps indicate when
it is possible to create a new console (via AllocConsole).


When FreeConsole is called, all handles that the process has
open to the console are closed.  Like most k32objs, if the 
console's refcount reaches zero, its k32obj destroy function
is called.  The destroy kills the xterm if one was open.

Also like most k32 objects, we assume that (K32OBJ) header is the
first field so the casting (from K32OBJ *to CONSOLE *)
works correctly.

FreeConsole is called on process exit (in ExitProcess) if 
pdb->console is not NULL.


BUGS
----
Console processes do not inherit their parent's handles.  I think
there needs to be two cases, one where they have to inherit
the stdin/stdout/stderr from unix, and one where they have to
inherit from another windows app.

SetConsoleMode -- UNIX only has ICANON and various ECHOs
to play around with for processing input.  Win32 has
line-at-a-time processing, character processing, and
echo.  I'm putting together an intermediate driver
that will handle this (and hopefully won't be any more
buggy then the NT4 console implementation).


================================================================

experimentation with NT4 yields that:

WriteFile
---------
	o does not truncate file on 0 length write
	o 0 length write or error on write changes numcharswritten to 0
	o 0 length write returns TRUE
	o works with console handles

_lwrite
-------
	o does truncate/expand file at current position on 0 length write
	o returns 0 on a zero length write
	o works with console handles (typecasted)

WriteConsole
------------
	o expects only console handles


SetFilePointer
--------------
	o returns -1 (err 6) when used with a console handle


FreeConsole
-----------
	o even when all the handles to it are freed, the win32 console
	  stays visible, the only way I could find to free it
	  was via the FreeConsole


Is it possible to interrupt win32's FileWrite?  I'm not sure.
It may not be possible to interrupt any system calls.