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GetMessage() in MFC console app

Posted on 2010-08-23
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Last Modified: 2013-11-20
Hi all,
I have an MFC console application, with main declared as follows:
int _tmain(int argc, _TCHAR* argv[])

Can I receive windows standard messages, key up/down etc.?
If I call GetMessage() it never returns (unless I send a message myself with PostThreadMessage), nothing even gets printed on the screen when I type - the thread is blocked, just waiting.

Any help is appreciated.
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Question by:darrgyas
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11 Comments
 
LVL 86

Expert Comment

by:jkr
ID: 33501287
Well, what are you trying to achieve?
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Author Comment

by:darrgyas
ID: 33501444
I need to shut the application down from a different thread, and I also need to have an option for the user to type, let's say, 'quit', push enter and exit that way.
0
 
LVL 8

Expert Comment

by:Anthony2000
ID: 33502237
GetMessage does block if there are not messages in the thread's msg queue. You could call PeekMessage and poll the msg queue. When you say a thread is going to send the message, it the thread owned by the same process?
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LVL 33

Expert Comment

by:pgnatyuk
ID: 33502693
>> I need to shut the application down from a different thread, and I also need to have an option for the user to type, let's say, 'quit', push enter and exit that way

So you don't need GetMessage in this console application. Make a code that will wait for the user input and parse it. If it will be the command you want to handle, you will send a message to another process, for example, WM_CLOSE. You can SendMessage, emulate keyboard, ... from this console application.
0
 

Author Comment

by:darrgyas
ID: 33502746
>>>> When you say a thread is going to send the message, it the thread owned by the same process?
Yes

>>>> o you don't need GetMessage in this console application. Make a code that will wait for the user input and parse it
getc() blocks, the only option that it leaves me is send keys from another thread - that is not reliable
0
 
LVL 33

Expert Comment

by:pgnatyuk
ID: 33502768
So, maybe, the console application was not a good choice?
Simple MFC dialog with few button, an editbox as a console if needed,... - it's not a lot of work.
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LVL 8

Expert Comment

by:Anthony2000
ID: 33502799
You could also just create an MFC dialog (with the window starting up hidden) like pgnatyuk suggested, then you could post a WM_CLOSE to the main window from your other thread.
0
 
LVL 8

Expert Comment

by:Anthony2000
ID: 33502803
Any reason why the app needs to be a console app?
0
 

Author Comment

by:darrgyas
ID: 33502870
>>>> Any reason why the app needs to be a console app?
Yes, and it's a good one - but this is outside of the scope of my question.

Maybe it's not possible?
How would you send keys to the main thread in the console app from another thread? Maybe I'm doing it wrong?
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LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 33503184
What about sending a CTRL_C_EVENT to ypour console handler to terminate?
#include <windows.h> 
#include <stdio.h> 
 
BOOL CtrlHandler( DWORD fdwCtrlType ) 
{ 
  switch( fdwCtrlType ) 
  { 
    // Handle the CTRL-C signal. 
    case CTRL_C_EVENT: 
      printf( "Ctrl-C event, exiting\n\n" );
      ExitProcess(0);
      return( TRUE );
 
    default: 
      return FALSE; 
  } 
} 
 
void main( void ) 
{ 
  if( SetConsoleCtrlHandler( (PHANDLER_ROUTINE) CtrlHandler, TRUE ) ) 
  { 
    printf( "\nThe Control Handler is installed.\n" ); 
 
    while( 1 ){ } 
  } 
  else 
    printf( "\nERROR: Could not set control handler"); 
}


// other thread:

  GenerateConsoleCtrlEvent(CTRL_C_EVENT,0);

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Author Comment

by:darrgyas
ID: 33503322
>>>> jkr
Gives me a first-time exception, but it works. Not quite what I was looking for, but it is a legitimate solution.
Thank you - helpful as always.
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