Chapter 3
Developing Your Application
VXI-1394 User Manual for Windows
3-8
ni.com
Note
viMemAlloc()
or
VXImemAlloc()
returns 32-bit aligned, page-locked,
continuous buffers which work efficiently with the move operations.
Shared Memory
In the Hardware Configuration settings for your controller in MAX, you
can share memory from your computer to the VXI bus. Right-click any
setting or consult the MAX online help for more information. You can
access shared memory on your computer using
viMemAlloc()
in VISA
(or
VXImemAlloc()
in the NI-VXI API). Use MAX to view the VXI
address where your shared RAM is allocated, or determine this information
programmatically using VISA’s
viGetAttribute()
.
NI-VXI API Notes
The following notes apply only if you are using the NI-VXI API. We
recommend that all new VXI/VME applications use the NI-VISA API,
but you can still develop with the older NI-VXI API for compatibility with
legacy code.
Compiler Symbols
You may need to define certain compiler symbols so that the NI-VXI
library can work properly with your program. The required symbol
indicates your operating system platform; for example,
VXINT
designates
the application as a Windows 2000/NT/XP/Me/98 application.
Note
LabWindows/CVI automatically defines the correct symbol. You do not need to
define
VXINT
when using LabWindows/CVI.
The additional symbol
BINARY_COMPATIBLE
is optional. It ensures that
the resulting application is binary compatible with other National
Instruments VXI controllers using the same operating system. This symbol
may cause a slight performance degradation when you use low-level
VXIbus access functions.
You can define these symbols using
#define
statements in your source
code or using the appropriate option in your compiler (typically either
-D
or
/D
). If you use
#define
statements, they must appear in your code
before the line that includes the NI-VXI API header
nivxi.h
.
