National Instruments NI-488.2 Benutzerhandbuch

You can use the 

ibwait

 function to obtain the current 

ibsta

 value or to 

suspend your application until a specified condition occurs on the GPIB. If 
you use 

ibwait

 with a parameter of zero, it immediately updates 

ibsta

 

and returns. If you want to use 

ibwait

 to wait for one or more events to 

occur, pass a wait mask to the function. The wait mask should always 
include the TIMO event; otherwise, your application is suspended 
indefinitely until one of the wait mask events occurs.

Win32 NI-488.2 applications can asynchronously receive event 
notifications using the 

ibnotify

 function. This function is useful if you 

want your application to be notified asynchronously about the occurrence 
of one or more GPIB events. For example, you might choose to use 

ibnotify

 if your application only needs to interact with your GPIB device 

when it is requesting service. After calling 

ibnotify

, your application 

does not need to check the status of your GPIB device. Then, when your 
GPIB device requests service, the NI-488.2 driver automatically notifies 
your application that the event has occurred by invoking a callback 
function. The callback function is registered with the NI-488.2 driver when 
the 

ibnotify

 call is made. 

ibnotify

 has the following function prototype:

ibnotify (

int ud,// unit descriptor

int mask,// bit mask of GPIB events

GpibNotifyCallback_t Callback,

// callback function    

void * RefData// user-defined reference data

)

Both board-level and device-level 

ibnotify

 calls are supported by the 

NI-488.2 driver. If you are using device-level calls, you call 

ibnotify

 

with a device handle for 

ud

 and a 

mask

 of RQS, CMPL, END, or TIMO. If 

you are using board-level calls, you call 

ibnotify

 with a board handle for 

ud

 and a 

mask

 of any values except RQS or ERR. The 

ibnotify

 mask bits 

are identical to the 

ibwait

 mask bits. In the example of waiting for your