> On Unix a program always starts with just stdin/stdout/stderr and
> has to
> open a connection to the X server to start using windows. On
> a program is either a "DOS" program or a "Windows" program. I don't
Technical term is "Console mode". DOS has nothing to do with it, and
good riddance! :)
> think it is possible, or at least it is not easy, to have a program
> starts in a DOS console and starts opening windows after that. Thus
> can't make Vim run in a console or open windows by adding a command
Actually, the only difference between a console and a windows mode
program is that the console mode program automatically gets a console.
It either attaches to the parent's console or has a console created for
it (if the parent isn't attached to a console). A "Windows" mode app is
born without a console. Otherwise, both systems are the same -- both can
do the same kind of GUIs and Windowing. A Windows Mode app can create a
console or attach itself to an existing console. Most of the time, that
works ok, but all too often we want to have our cake and eat it, too.
I keep on running into this -- how can you make a "dual" mode
application? I've never tried it, but I think it is possible. Three
possible solutions come to mind:
1. Create a Windows mode program. At startup, decide whether you really
want to be Windows or Console. If you want to be Windows, no problem,
just do what you usually do. If you want to be a console app, call
AllocConsole() (this allocates a console and attaches the process to it),
and then continue on as a console app. The only issue is that the C
Runtime might not be immediately conviced that you are a console app. I
haven't tried it, but I find it easy to imagine that the C Runtime
startup code could set itself up differently depending on whether you are
a console app or a windows app. I don't think it would be a problem, but
it is possible. If it is a problem, I think I know what the workaround
The only disadvantage to this is that you are on a different console from
the process that spawned you. The expected behavior would be to have a
new console pop up if you start vim from a GUI, but for vim to be in the
original console if started from the command line.
2. Create a console mode program. At startup, if you decide that you
want to be a Windows app after all, just call FreeConsole() to detach
from the console you're attached to.
The disadvantage here is that you'll start out a console no matter what.
If you start from the command line, this isn't a problem -- you start
with the parent's console, then detach from it, and all is well. But if
you are spawned by a process without a console, a new console will be
created for you. You can detach from it immediately, but there will be a
brief flicker of a console popping up and then disappearing.
3. Create a Windows mode program. If you want to be on a console, call
AttachConsole(ATTACH_PARENT_PROCESS). I think the call will fail if the
parent doesn't have a console, in which case you just call
So now you're wondering why I didn't just give #3. Turns out that this
didn't become an option until Windows XP. Windows 2000 and earlier
cannot attach to an existing console -- processes either take the console
they are born with or they create a new console.
> It would be possible to make a wrapper that starts vim.exe or
> depending on an argument, but you still need the two executables,
> it doesn't make much sense.
Strangely enough, it seems that Microsoft agrees with you. Check this
out if you have Visual Studio. If you have 6.0, go to Program
Files\Microsoft Visual Studio\Common\MsDev98\bin and look at MSDEV. If
you have 7.x, go to Program Files\Microsoft Visual ...\Common7\IDE and
look at DEVENV.
Note that there are two versions of each -- msdev.EXE and msdev.COM,
devenv.EXE and devenv.COM. COM-type programs are a very old style, and
are DOS only. It turns out that these really aren't COM programs --
they're EXE style programs that have been renamed. Windows uses the file
extension to determine whether or not a file is executable, but looks
inside the file to figure out how to execute it, so it runs the COM file
properly as if it were an EXE program. And since by default the system
looks for COM files before it looks for EXE files (legacy rule that was
instituted while I was still in kindergarten), if you type MSDEV at the
command prompt, it will run the COM program. But all of the shortcuts
are to the EXE.
The COM program is a console mode app. The EXE program is a windows mode
app. Microsoft is using method #2 from above. All of the shortcuts go
to the EXE version so that you don't get the console popping up if you
start MSDEV from a GUI. But if you double-click on MSDEV.COM, you'll see
a brief flicker of a console appearing and disappearing, then MSDEV.EXE
will start up.
All MSDEV.COM is doing is starting up MSDEV.EXE. The purpose is so that
the main program, MSDEV.EXE doesn't have the flickering console popup,
yet MSDEV can still be used as a command line utility. MSDEV.COM simply
starts MSDEV.EXE, passing it the exact same command line parameters as it
got. Even though MSDEV.EXE can't have MSDEV.COM's console, it DOES
inherit MSDEV.COM's StdIn, StdOut, and StdErr handles. So it can't do
ncurses-style stuff, but it CAN send text to the console, which is all it
needs to be able to do.
MSDEV.COM does have one job to do: it has to decide whether or not to
wait for MSDEV.EXE to exit. If the user just typed MSDEV with no
parameters or with the name of a source file, he/she probably just wants
to start the IDE, so MSDEV.COM starts the IDE, then exits while the IDE
continues running. But if the user types MSDEV MyProject.dsp /MAKE
Debug, they want MSDEV to build MyProject. So MSDEV.COM starts the IDE,
then waits for it to exit before exiting itself. This way, you can run
MSDEV /MAKE from a batch file, and the batch file won't continue until
the make has completed.
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