Win32 进程间通信分配

Question

I need to do a C++ assignment, but I'm pretty much new to Win32 IPC. I did a little bit of research yesterday, but I cannot find the thing I'm searching for.

Basically, I need two programs, the first creates a FileMapping with paging file, waits a buffer, display the buffer, and closes it.

The second connects to the Communication Channel, writes the buffer to the first program, and then closes.

The closest thing I've come to is this resource: IPC Communication but the guy there uses pipes instead of communication channels using paging file.

Also, I found that I can open a FileMapping with paging file pretty much like this:

TCHAR szMapFileName[] = _T("Local\\HelloWorld"); 

HANDLE hMapFile = CreateFileMapping( 
       INVALID_HANDLE_VALUE,       

       NULL,                      // Default security 
       PAGE_READWRITE,            // Read/write access 
       0,                         // Max. object size 
       BUFFER_SIZE,               // Buffer size  
       szMapFileName              // Name of mapping object);

If somebody can provide a little help that would be very valuable(maybe a skeleton of an app?). I tried to do some research yesterday, but in vain.

Thanks

Answer 1

CreateFileMapping() , OpenFileMapping() and MapViewOfFile() are indeed the functions you need to call to allocate a shared memory buffer.

The first app must:

• Create the File Mapping.
• Create a synchronization object, preferably an Event, to wait on it.
• Create an additional thread, which will be waiting for the Event to be signaled. Doing this in the main (UI) thread would block the application.
• When the Event is signaled, post a custom message ( WM_APP+nnn ) to the main thread, to display the contents of the buffer.
• It's a matter of specs or design what to do after this point, eg exit the application, just not be waiting for the buffer to receive data anymore, clear the event and wait again, etc.

The second app must:

• Open the File Mapping and the Event. If failed, display an error message or warning and exit.
• Write the data to the shared memory buffer.
• Signal the Event.
• Exit.

It could be further improved, eg the second app may not write to the buffer if the event is not in the nonsignaled state.