| # Adding the Interface to Tcl To add the Empress extension to a Tcl/C application (for example, to create a Tcl shell which includes the Empress extension), the procedure `Etsql_Init()` should be called:
    	int	Etsql_Init (Tcl_Interp *interp)
This procedure initializes the Empress package and registers a new Tcl command: `etsql`. It also renames the original Tcl `exit` command, and creates a new `exit` command. This new `exit` command will perform database clean-up before calling the original `exit` command. `Etsql_Init()` returns `TCL_OK` on success, or `TCL_ERROR` on failure. Note: this version of the Empress Tcl/Tk interface does not support multiple Tcl interpreters. ### Example Here's the source of `tclsh` modified to use the Empress interface:
    	#include
    	#include

    	main	(argc, argv)
    		int	argc;
    		char	*argv[];
    	{
    		Tcl_Main (argc, argv, Tcl_AppInit);
    		exit (0);
    	}

    	int	Tcl_AppInit (interp)
    		Tcl_Interp	*interp;
    	{
    		int	Sql_Init();

    		if (Tcl_Init (interp) == TCL_ERROR)
    			return TCL_ERROR;

    		if (Etsql_Init (interp) == TCL_ERROR)
    			return TCL_ERROR;

    		return TCL_OK;
    	}