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Before you exit your application, stop communication to shut down 
DeviceNet connections to remote devices. Use the Interface Object to 
call the 

ncOperateDnetIntf

 function with the 

Opcode

 parameter set 

to

Stop

.

Before you exit your application, close all NI-DNET objects using the 

ncCloseObject

 function.

The NI-DNET software allows multiple NI-DNET applications to use the 
same interface object simultaneously, as long as the interface configuration 
remains the same. For example, you can run both the 

SingleDevice

 

example and SimpleWho on DNET0 as long as the 

Interface MacId

, 

BaudRate

, and 

PollMode

 parameters are the same in both applications 

(SimpleWho uses a 

PollMode

 of 

Scanned

). Similarly, you can open up 

two copies of the 

SingleDevice

 example and communicate with two 

different devices as if it were through a single application. These same rules 
apply to the I/O Object and the Explicit Messaging Object.

As long as all the configuration attributes are the same, any object can be 
opened multiple times. You can enable only one notification or wait 
(through 

ncWaitForState

, 

ncCreateNotification

, or 

ncCreateOccurrence

 functions) for an object, no matter how many 

handles you have opened for that particular object. For example, if you are 
running two copies of the 

SingleDevice

 example on the same interface 

with the same connection types, the notification triggers in only one 
application at a time.

The synchronization of events and the protection of the object I/O data is 
the responsibility of the application developer. Similarly, the application 
performance might change based on the number of objects open and the 
frequency of API calls made in each application. For example, several calls 
to 

ncGetDnetAttribute

 in one application might slow down another 

application running on the same interface.

To ensure proper clean up of all the objects, each open call to an object 
should be matched by a close call to the same object, and each call to 

ncOperateDnetIntf 

with 

NC_OP_START

 code should be matched by 

a call to the same function with 

NC_OP_STOP

 code.