National Instruments NI-488.2 ユーザーズマニュアル

The language header file defines each of the 

ibsta

 status bits. You can 

test for an 

ibsta

 status bit being set using the bitwise 

and

 operator 

(

&

in C/C++). For example, the 

ibsta

 ERR bit is bit 15 of 

ibsta

.

To check for an NI-488.2 error, use the following statement after each 
NI-488.2 call:

if (ibsta & ERR)

printf("NI-488.2 error encountered");

If the ERR bit is set in 

ibsta

, an NI-488.2 error has occurred. When an 

error occurs, the error type is specified by 

iberr

. To check for an NI-488.2 

error, use the following statement after each NI-488.2 call:

if (ibsta & ERR)

printf("NI-488.2 error %d encountered", iberr);

The value in 

iberr

 is meaningful as an error only when the ERR bit is set in 

ibsta

, 

indicating that an error has occurred. 

For more information about error codes and solutions, refer to Chapter 5, 

, or Appendix C, 

The count variables are updated after each read, write, or command 
function. In addition, 

ibcnt

 and 

ibcntl

 are updated after specific 

488.2-style functions in certain error cases. Refer to the NI-488.2 Help 
function reference for an explanation of how each function uses the count 
variables.

ibcnt

 is defined to be the type 

int

 while 

ibcntl

 is the size of type 

long 

int

. For all cases, if the sizes of 

ibcnt

 and 

ibcntl

 are the same, 

ibcnt

 

and 

ibcntl

 are equal. If the size of 

ibcnt

 is smaller than the size

of 

ibcntl

, 

ibcnt

 is equal to the low-order bits of 

ibcntl

. For 

cross-platform compatibility, all applications should use 

ibcntl

. 

DTAS

1

2

brd

Device Trigger State 

DCAS

0

1

brd

Device Clear State

Table 4-1.  Status Word Layout (Continued)