NO

Author Topic: Closing console window  (Read 5716 times)

golite

  • Guest
Closing console window
« on: October 05, 2013, 06:48:25 AM »
I have a console window that starts up and runs with my Windows app.
I currently have to close the windows app and then close the console also.
Is there a way to close the console window through the WM_CLOSE command?

I am interested in learning how Pelles makes the console stay active. I used to have to cause the console to stay open by using some kind of read or get command.

Offline jj2007

  • Member
  • *
  • Posts: 536
Re: Closing console window
« Reply #1 on: October 05, 2013, 08:30:02 AM »
If I build a standard GUI app (subsystem windows) and insert
   AllocConsole();
somewhere at the beginning of main(), the console window closes when I close the GUI window.

How do you get the console window?

Offline TimoVJL

  • Global Moderator
  • Member
  • *****
  • Posts: 2091
Re: Closing console window
« Reply #2 on: October 05, 2013, 09:13:41 AM »
I have a console window that starts up and runs with my Windows app.
I currently have to close the windows app and then close the console also.
Is there a way to close the console window through the WM_CLOSE command?

I am interested in learning how Pelles makes the console stay active. I used to have to cause the console to stay open by using some kind of read or get command.
This happens only in PellesC IDE ?, (IDE feature to commandline programs)

How do you get the console window?
Just use this in GUI program (UNICODE)
Code: [Select]
...
#pragma comment(linker, "-subsystem:console")
#pragma comment(linker, "-entry:wWinMainCRTStartup")
...
May the source be with you

Offline jj2007

  • Member
  • *
  • Posts: 536
Re: Closing console window
« Reply #3 on: October 05, 2013, 10:02:55 AM »
Just use this in GUI program (UNICODE)
Code: [Select]
...
#pragma comment(linker, "-subsystem:console")
#pragma comment(linker, "-entry:wWinMainCRTStartup")
...

Yes, this works fine, but it produces the behaviour the OP didn't want, i.e. the console remains open until you press a key. AllocConsole behaves better in this respect, but of course, you need an alternative to printf:
   AllocConsole();
   WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE), "Hello", 5, 0, 0);

golite

  • Guest
Re: Closing console window
« Reply #4 on: October 06, 2013, 03:41:52 AM »
I now have removed the pragma statements and I only need the AllocConsole() and the WriteConsole() to achieve my intentions. This does the trick well.

Thanks Again.

Offline TimoVJL

  • Global Moderator
  • Member
  • *****
  • Posts: 2091
Re: Closing console window
« Reply #5 on: October 06, 2013, 09:27:43 AM »
In that way you loose that log in new console.
Simple TRACE macro:
Code: [Select]
#ifndef NDEBUG
//#define TRACE(x) OutputDebugString(x)
#define TRACE(x) WriteStdOut((x))
void __cdecl WriteStdOut(TCHAR *szTxt)
{
static HANDLE hStdOut = 0;
if (!hStdOut) {
AllocConsole();
hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
}
WriteConsole(hStdOut, szTxt, lstrlen(szTxt), 0, 0);
}
#else
#define TRACE(x)
#endif
Usage:
Code: [Select]
TRACE("My TRACE comment\n");
« Last Edit: October 06, 2013, 09:29:47 AM by timovjl »
May the source be with you

czerny

  • Guest
Re: Closing console window
« Reply #6 on: April 14, 2014, 11:55:17 AM »
This is an example I have found on the net. printf() is working.

Only problem I see so far is scanf(). It looses the first character of the input. 123 gives 23. 'Test' gives 'est'.

Offline frankie

  • Global Moderator
  • Member
  • *****
  • Posts: 2098
Re: Closing console window
« Reply #7 on: April 14, 2014, 01:12:42 PM »
Add a flush of stdin:
Code: [Select]
// redirect unbuffered STDIN to the console
lStdHandle = (long)GetStdHandle(STD_INPUT_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT | _O_RDONLY);
fp = _fdopen( hConHandle, "r" );
*stdin = *fp;
setvbuf( stdin, NULL, _IONBF, 0 );
fflush(stdin); //Add Flush
It is better to be hated for what you are than to be loved for what you are not. - Andre Gide

czerny

  • Guest
Re: Closing console window
« Reply #8 on: April 14, 2014, 03:10:13 PM »
Thanks!

aardvajk

  • Guest
Re: Closing console window
« Reply #9 on: April 14, 2014, 08:39:35 PM »
You don't need 6 lines to redirect a stream, 3 will do them all, without having to employ the undefined behaviour of fflush(stdin)
Code: [Select]
freopen("CONIN$", "r", stdin);
freopen("CONOUT$", "w", stdout);
freopen("CONOUT$", "w", stderr);

Offline frankie

  • Global Moderator
  • Member
  • *****
  • Posts: 2098
Re: Closing console window
« Reply #10 on: April 15, 2014, 11:05:12 AM »
You don't need 6 lines to redirect a stream, 3 will do them all, without having to employ the undefined behaviour of fflush(stdin)
Yes you're right :), for std-C the statement has an undefined behaviour. But in WINNT it is an extension to the standard.
From MS here
Code: [Select]
   // You must flush the input buffer before using gets.
   // fflush on input stream is an extension to the C standard

Code: [Select]
freopen("CONIN$", "r", stdin);
freopen("CONOUT$", "w", stdout);
freopen("CONOUT$", "w", stderr);
This doesn't work.
freopen works when stdin, stdout and stderr already  refers to valid opened streams, that is true when you start a console program, but fails when allocating a console in a GUI subsystem.
When you allocate a console from a GUI program the standard streams don't point to valid files while the allocated console have opened its own streams.
The long code scope is then to collect the actual OS file handle and associate it to C-runtime streams stdin, stdout, stderr.
This tecnique is MS original as showed here
« Last Edit: April 15, 2014, 12:14:35 PM by frankie »
It is better to be hated for what you are than to be loved for what you are not. - Andre Gide