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Output console while using win32

Started by Metal Typhoon 7 replies 300+ views
Original Post
Metal Typhoon
Metal Typhoon
is there such way that u can open the console and output a variable while keep using your compiler for win32 ?
Metal Typhoon
dalleboy
dalleboy
Use AllocConsole to open a console, use WriteFile to print to the console.

    
AllocConsole();
const char* szMessage = "The message\nLalala\n";
WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), szMessage, strlen(szMessage), NULL, NULL);


NOTE1: Only call AllocConsole once.
NOTE2: If you close the console, you close the other program also.
NOTE3: There is a way around NOTE2, using GetSystemMenu and EnableMenuItem.

EDIT1: Added notes.


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[edited by - dalleboy on January 3, 2003 2:17:07 PM]
Metal Typhoon
Metal Typhoon
can you give me a "why" that i have to close the app? please
Metal Typhoon
dalleboy
dalleboy
Opps, if you press the [X] in the upper right of the console, or if you press Alt-F4 on the console, the same thing will happen to the program that allocated the console. They are like siamese twins, if one die the other (most probably) also dies.

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krez
krez
just out of curiosity, is there a way to uise this console with c++ iostream? i.e. "cout << blah;"? or must you use WriteFile()?
--- krez ([email="krez_AT_optonline_DOT_net"]krez_AT_optonline_DOT_net[/email])
dalleboy
dalleboy
Hmm, I tried it just a minute ago, but it didn''t work. Perhaps a special iostream for that purpose? i.e. basic_icstream, basic_ocstream and basic_cstream for Console streams? I''ll have a look at it.


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Oxyacetylene
Oxyacetylene
I found this code somewhere on the net (I forget where), it redirects printf, cout, cin, etc to a console created with AllocConsole


  
using namespace std;

AllocConsole();

int hConHandle;
long lStdHandle;
FILE* fp;

// redirect unbuffered STDOUT to the console


lStdHandle = (long)GetStdHandle(STD_OUTPUT_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "w" );
stdout = *fp;
setvbuf( stdout, NULL, _IONBF, 0 );

// redirect unbuffered STDIN to the console

lStdHandle = (long)GetStdHandle(STD_INPUT_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "r" );
*stdin = *fp;
setvbuf( stdin, NULL, _IONBF, 0 );

// redirect unbuffered STDERR to the console

lStdHandle = (long)GetStdHandle(STD_ERROR_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "w" );
*stderr = *fp;
setvbuf( stderr, NULL, _IONBF, 0 );


// make cout, wcout, cin, wcin, wcerr, cerr, wclog and clog 

// point to console as well

ios::sync_with_stdio();


Then when you're done


  
FreeConsole()


[edited by - Oxyacetylene on January 3, 2003 3:17:26 PM]
krez
krez
Oxyacetylene: i get an error on the line "stdout = *fp;". it says "lvalue required on left side"...
--- krez ([email="krez_AT_optonline_DOT_net"]krez_AT_optonline_DOT_net[/email])
risingdragon3
risingdragon3
if you want a ostream iostream not using Oxyacetylene's code:
Writing a simple stream_buf to allow iostreams with a console window is not in and of itself terribly difficult.
[begin plug]
For example, libGDN has an stream_buf that outputs to any FILE*, and also contains a stream_buf adaptor that makes writing stream_buf's very easy: just implement Write() and your done. Have a look at the CVS tree and the examples, io*.
Now, libGDN doesn't currently have a console stream, but I've been working on that and format manipulators - color, fore and back, underline, etc. and possibly positional - that the win32 API allows you to mess with. It shoudl be done once I get this damn windowing system to work correctly...
[end plug]

Now, if you dont' wanna use the libGDN adaptor, have a look at stream_buf - you'll need to implement overflow() I think to call Write() on the console. Then subclass basic_ostream and in the constructor, call basic_ostream(&console_buffer); where consolebuffer is an instance of your class.
There's tons of info on the net; try a google.

Ooops: libgdn: here
[edited by - risingdragon3 on January 3, 2003 8:03:33 PM]

[edited by - risingdragon3 on January 3, 2003 8:04:10 PM]

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