Q: How can I limit my application to one instance?
A: You need to create a named mutex semaphore when you start your application. When the second one starts it tries to get access to the mutex but will fail...
Code:
// app.h
class CYourApp : public CWinApp
{
...
private:
HANDLE hMutex;
};
// app.cpp
BOOL CYourApp::InitInstance()
{
// Create mutex
hMutex = ::CreateMutex(NULL, TRUE, "GlobalMutex");
switch(::GetLastError())
{
case ERROR_SUCCESS:
// Mutex created successfully. There is no instance running
break;
case ERROR_ALREADY_EXISTS:
// Mutex already exists so there is a running instance of our app.
return FALSE;
default:
// Failed to create mutex by unknown reason
return FALSE;
}
}