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Process Pre-Initialization

Glossary Item Box

Description

When an application starts, it must instantiate a CLIP process and start it. The application must then block until all of its threads (CLiP, GUI etc) terminate.

Process1Process mProcess;
mProcess.Startup();

The Startup() function recursively creates, initializes and activates all of the CLIP circuitry for the process. This is a complex procedure (the reader need not know all of the details), and is broken down into a number of asynchronous events: Prestart, Create, Integrate, Initialise, Connect, Activate (and Exit). The scheduling of these events depend on the build type (Master,  Slave etc).

 

Ie.

  • Master runs Prestart
  • Master creates definitive instances of ALL circuit objects
  • Master Initializes all definitive data sets
  • Master Activates all local methods and threads
  • Master waits for slaves to connect
  • Master tells slave to start creation/initialization
  • Master waits for slave to initialize
  • Master starts slave (master may need to wait for a minimum number of slaves)
  • Master sends jobs to active slaves
  • More slaves may connect, each needs to create/initialise before it can be activated

 

  • Slave runs Prestart
  • Slaves connects to master
  • Slave creates instances all its definitive circuit objects, but not slaveable objects or non-definitive objects
  • Slave initializes all its definitive data sets
  • Slave reports initialized to Master
  • Slave waits for job
  • Slave processes job
  • Slave reports results back to master

It is often necessary for code to be activated before the CLIP process starts (Eg. to initialise array dimensions (calculated/read from file)). This can be done in the Prestart function (see Runtime Attribution)

bool MyProc1Process::OnPrestart()
{
   FILE* fp = fopen( INI_FILE, "r" );

   fscanf( fp, "%d", &gARRAY_DIM_1 );
   fclose( fp );

   return TRUE;
} 

 

Whenever a GUI is being used, it is almost always necessary for the GUI thread to be started before the CLIP Process (the GUI may need to stop a slave application if it can't connect to a master). Thus the main application thread needs to create a GUI dialog and activate it (non-model) (see GUI Programming) before the call to process Startup.

CMyDlg1Dlg* dlg = new CMyDlg1Dlg();

m_pMainWnd = dlg;
dlg->Create( IDD_GUI_DIALOG );

mProcess.Startup();

 

To get GUI events from the GUI message pump to CLIP and vice-versa, CLIP needs to know about the GUI and the GUI about CLiP. This is achieved in two ways,

  1. Register the main GUI dialog with the CLiP process
  2. Overload the GUI dialog's message pump handler.

CMyDlg1Dlg::OnInitDialog()
{
   ...
   CLIP::SetCallbackWindow( this->GetSafeHwnd(), this );
}

LRESULT CMyDlg1Dlg::DefWindowProc( UINT message, WPARAM wParam, LPARAM )
{
   CLIP::ProcessPumpMessage( message, wParam, lParam );

   return CDialog::DefWindowProc( message, wParam, lParam );
}