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

© National Instruments Corporation

With Visual Basic, you can access the traditional NI-488.2 calls as 
subroutines, using the BASIC keyword 

CALL

 followed by the traditional 

NI-488.2 call name, or you can access them using the 

il

 set of functions. 

With some of the NI-488.2 calls (for example 

ibrd

 and 

Receive

), the 

length of the string buffer is automatically calculated within the actual 
function or subroutine, which eliminates the need to pass in the length as 
an extra parameter. For more information about function syntax for Visual 
Basic, refer to the NI-488.2 online help. For instructions on accessing the 
online help, refer to the 

 section in 

Before you run your Visual Basic application, include the 

niglobal.bas

 

and 

vbib-32.bas

 files in your application project file.

The following sections describe how to use direct entry with C.

gpib-32.dll

 exports pointers to the global variables and all of the 

NI-488.2 calls. Pointers to the global variables (

ibsta

, 

iberr

, 

ibcnt

, 

and

ibcntl

) are accessible through these exported variables:

int *user_ibsta;

int *user_iberr;

int *user_ibcnt;

long *user_ibcntl;

Except for the functions 

ibbna

, 

ibfind

, 

ibrdf

, and 

ibwrtf

, all 

the NI-488.2 call names are exported from 

gpib-32.dll

. Thus, to use 

direct entry to access a particular function and to get a pointer to the 
exported function, you just need to call 

GetProcAddress

 passing the 

name of the function as a parameter. For more information about the 
parameters to use when you invoke the function, refer to the NI-488.2 
online help. For instructions on accessing the online help, refer to the 

 section in 

.

The functions 

ibbna

, 

ibfind

, 

ibrdf

, and 

ibwrtf

 all require an 

argument that is a name. 

ibbna

 requires an interface name, 

ibfind

 

requires an interface or device name, and 

ibrdf

 and 

ibwrtf

 require a file 

name. Because Windows 2000/NT supports both normal (8-bit) and 
Unicode (16-bit) characters, 

gpib-32.dll

 exports both normal and 

Unicode versions of these functions. Because Windows 98/95 does not