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Browse - programming tips - win32 send numbers inter process

Date: 2008nov10
Platform: win32
Keywords: interprocess

Q.  How do I send data from one Windows process to another?

A.  If you just want to send 2 numbers do this:

// This is the class name you used in your InitApplication() routine
// of the receiver.  Typically win32 apps have routine named
// InitApplication() that calls RegisterClass() with a class name
// and other stuff
static LPCSTR gszReceiverClass = "ReceiverClass"; // CHANGE THIS!!!!

// The Receiver needs to process this windows message
#define WM_TWO_NUMBERS_TO_RECEIVER	(WM_APP+1)

BOOL SendReceiverNumbers(const WPARAM n1, const LPARAM  n2)
{
	HWND hwndRec;

	if ((hwndRec = FindWindow(gszReceiverClass, NULL)) == NULL) return
FALSE;
	return PostMessage(hwndRec, WM_TWO_NUMBERS_TO_RECEIVER, n1, n2);
}

If your numbers are small you can actually send 4 like this:

BOOL SendReceiver4Numbers(const WORD a, const WORD b, const WORD c, const WORD d)
{
	return SendReceiverNumbers(MAKEWPARAM(a,b), MAKELPARAM(a,b));
	// Use LOWORD() on the receiving side
}

A Win32 Receiver does this:

        case WM_TWO_NUMBERS_TO_RECEIVER:
                {
			int n1 = wParam;
			int n2 = lParam;

			// Do stuff with n1 and n2
                }
                break;

If you want to pass more look at
http://www.davekb.com/search.php?target=WM_COPYDATA

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