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Using Win32 Console

Posted on 2001-06-14
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Last Modified: 2012-06-27


I want to use the Win32 Console but when I call GetStdHandle, I get a handle that seems to be not valid.

The code should compile and show the following error after run:

Error: Could not receive buffer information.  --> The handle is invalid.


Did I forget any init step ... ?




#include <windows.h>
#include <iostream.h>

void error(string s) {
    LPVOID lpMsgBuf;
    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS, 0, GetLastError(), MAKELANGID(LANG_NEUTRAL,
        SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0,0);
    std::cout << "Error: " << s << "  --> " << (std::string)(LPCTSTR)lpMsgBuf;
};

HANDLE _V_consoleOutputHandle, _V_consoleInputHandle;

void main()
{
     CONSOLE_SCREEN_BUFFER_INFO __csbi;

     _V_consoleOutputHandle = GetStdHandle(STD_OUTPUT_HANDLE);
     if (_V_consoleOutputHandle == INVALID_HANDLE_VALUE)
         error("Could not create output buffer handle.");
     _V_consoleInputHandle = GetStdHandle(STD_INPUT_HANDLE);
       if (_V_consoleInputHandle == INVALID_HANDLE_VALUE)
         error("Could not create input buffer handle.");

     if ( ! GetConsoleScreenBufferInfo(_V_consoleOutputHandle, &__csbi) )
         error("Could not receive buffer information.");

    // .......
}


0
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Question by:bormuth
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8 Comments
 
LVL 3

Expert Comment

by:jlsjls
ID: 6190213
0
 
LVL 5

Accepted Solution

by:
proskig earned 50 total points
ID: 6190234
I have compiled your snippet on my machine and it worked. I had to change it to:

#include <windows.h>
#include <iostream>
#include <string>

void error(std::string s) {
   LPVOID lpMsgBuf;
   FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
       FORMAT_MESSAGE_IGNORE_INSERTS, 0, GetLastError(), MAKELANGID(LANG_NEUTRAL,
       SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0,0);
   std::cout << "Error: " << s << "  --> " << (std::string)(LPCTSTR)lpMsgBuf;
};


The rest was find. Try to debug and see actual value of _V_consoleOutputHandle. On my machine it was 7.
0
 
LVL 2

Expert Comment

by:MadYugoslav
ID: 6190239
Try to call GetConsoleScreenBufferInfo right after You get handle of output.
If it work it seems that your identifiers are to long for your compiler settings.
Make identifiers for handles shorter or set specific option to make them available to be longer then now.
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Author Comment

by:bormuth
ID: 6190300


I used a shorter handle name nad even called GetConsoleScreenBufferInfo right after handle creation. The handle value is 0000044 but this still is NOT valid.

I use Borland C++ 5.5 and Windows 2000.

0
 
LVL 2

Expert Comment

by:MadYugoslav
ID: 6190322
I made empty console application on Visual C with:

#include "stdafx.h"
#include <windows.h>
#include <iostream.h>

HANDLE _V_consoleOutputHandle, _V_consoleInputHandle;
void main()
{
   CONSOLE_SCREEN_BUFFER_INFO __csbi;
   int err=0;

   _V_consoleOutputHandle = GetStdHandle(STD_OUTPUT_HANDLE);
   if (_V_consoleOutputHandle == INVALID_HANDLE_VALUE)
      err=1;
   _V_consoleInputHandle = GetStdHandle(STD_INPUT_HANDLE);
   if (_V_consoleInputHandle == INVALID_HANDLE_VALUE)
      err=1;
   if ( ! GetConsoleScreenBufferInfo(_V_consoleOutputHandle, &__csbi) )
      err=1;
   printf("%d", err);
   getchar();
}

and output is 0 (OK).
0
 
LVL 2

Expert Comment

by:MadYugoslav
ID: 6190326
May be You can try to change declaration for main function:

void main(void)

or

void main(int argc, char* argv[])
0
 

Author Comment

by:bormuth
ID: 6190347


OK

When I run the programm in a full screen 80*25 DOS window it works. But when I run it in a Console window (in my case 80*40) it doesn't.
0
 

Author Comment

by:bormuth
ID: 6190380

OK - it works


This code only runs on Win95 and following. My Console window was set to DOS mode ...

I gave th points to proskig because he gave me the idea that the code should work ..
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