Retreive a message from a Create​Process ?

Is it possible to create a process, an MFC application, and from that MFC application send message back to the programme that create the process ?

The goal is to be able to run the MFC application with a UI or in a console. So I create a console app (a.com) that launch the MFC application (a.exe) with a swith to run in console mode, but how can the MFC app send message back to a.com so that message get display in the console ?

Thanks.

By message you mean Windows Message?  WM_USER+X ?

Why would the console app be called a.com? Com executables are strictly a DOS concept, they don't exist in Windows.

For exchanging data between two processes, look into Interprocess Communication mechanisms such as pipes or shared memory.

ido.ran said:

By message you mean Windows Message?  WM_USER+X ?

Or you mean to pass a string which will be display in the console?

I want to pass string to be display in the console.

The app.com and app.exe is a trick that I read from the Internet to have the same app in console and UI, but both app contain all the business logic. It is not what I want. I can create a console.exe and app.exe. It doesn't matter.

cro said:

ido.ran said:

*snip*

I want to pass string to be display in the console.

The app.com and app.exe is a trick that I read from the Internet to have the same app in console and UI, but both app contain all the business logic. It is not what I want. I can create a console.exe and app.exe. It doesn't matter.

AndyC said:

cro said:

*snip*

A far less complicated way is just to use the Console class in .NET or standard out in a native executable.

cout has no effect in a MFC application, there is no console to print the text to.

cro said:

AndyC said:

*snip*

cout has no effect in a MFC application, there is no console to print the text to.

AndyC said:

cro said:

*snip*

Ah, yes, MFC. There is some sample code for attaching to the console here. That should do the trick.

There's something that didn't work. If I wan't to save it in a file, the text gets display in the console and the file is not created at all.

c:\>UI.exe >test.txt

This is the test code that I add to the InitInstance method:

HANDLE hStdout;
LPSTR lpszPrompt1 = "Hello world !";
DWORD cWritten;

if (!AttachConsole(ATTACH_PARENT_PROCESS))
{
    AfxMessageBox(_T("Erreur: ATTACH_PARENT_PROCESS"), MB_OK);
    exit(1);
}

hStdout = GetStdHandle(STD_OUTPUT_HANDLE);
if (hStdout == INVALID_HANDLE_VALUE)
{
    AfxMessageBox(_T("Erreur: INVALID_HANDLE_VALUE"), MB_OK);
    exit(1);
}

if (!WriteFile( 
    hStdout, // output handle 
    lpszPrompt1, // prompt string 
    lstrlenA(lpszPrompt1), // string length 
    &cWritten, // bytes written     
    NULL))
{
    AfxMessageBox(_T("Erreur: WriteFile"), MB_OK);
    exit(1);
}

return FALSE;

Matthew van Eerde said:

cro said:

*snip*

> c:\>UI.exe >test.txt

Hmmm... what happens if you do

c:\>UI.exe 2>&1 > test.txt

Finaly I found a solution starting from a Process class that I found on this page.