Chapter 7
Using the NI-VXI/VISA Software
7-4
www.ni.com
System Configuration Functions
The System Configuration functions provide the lowest-level initialization
of your VXI controller. For NI-VXI, use the
InitVXIlibrary()
function
at the start of each application and the
CloseVXIlibrary()
function at
the end of each application. For NI-VISA, use
viOpenDefaultRM()
at the start of each application and the
viClose()
function at the end of
each application.
Compiling Your C Program for NI-VXI/VISA
You can use the sample programs included with the NI-VXI software as a
starting point to develop your own C program that uses NI-VXI functions.
First, look over and compile the sample programs using the makefile
provided to get familiar with how the functions operate. The example
programs are broken into multiple files, and each one shows how to use
different groups of functions. You can then modify the sample programs to
try out different aspects of the NI-VXI software.
The sample programs for the Linux CC compiler are in the
/usr/local/nivxi/examples
directory for NI-VXI and
/usr/local/vxipnp/linux/NIvisa/Examples
directory for
NI-VISA.
The easiest way to compile the sample programs is to use the makefile
included with the NI-VXI/VISA software. For example, go to the
examples
directory and type
make
.
Symbols
You may need to define a symbol so that the NI-VXI library can work
properly with your program. The
VXILINUX
symbol is required for NI-VXI
applications, but not NI-VISA applications.
VXILINUX
designates the
application as a Linux NI-VXI application. You can define this symbol
using a
#define
statements in the source code or you can use
the
-D
option in your compiler. If you use a
#define
statement, you must
define the symbol before including the NI-VXI header file
nivxi.h
. If you
use the makefiles to compile the sample program, the makefile already
defined the necessary symbol.
