Need example or info for using file mapping in LabView

[KH]

Need example or info for using file mapping in LabView. I have a C++ executable that uses file mapping for its data output and that data output is to be the input into my LabView VI. I semi-understand file mapping from the C++ side, but no clues from the LabView side. Any help would be appreciated.

[Randy_H]

KH,

What kind of file mapping are you talking about? Are you using "my.exe >> output.txt"? or something different?

Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

[KH]

What I have is a C++ executable (I didn't write) that continuously updates data via windows file mapping to virtual memory and I need to get access (retrieve) that data via LabView 6 to be used in a VI. The file mapping is that of low-level threads using variables like m_hFileMapping and m_hMutex and functions like MapViewOfFile() and CreateMutex(). I have printouts of the executable and thus the variables values (static and non-static).

[Randy_H]

You could use Win 32 API calls using the Call Library Function Node in the Advanced palette. That may be the best way to access functions like these.

Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

[KH]

File mapping in LV is easiest using Code Interface Nodes and using the Win32 API's in a *.c file. The trick is to create a *.mak file with the following information:
name=CIN_NAME
type=CIN
cinlibraries=Kernel32.lib
CINTOOLSDIR=ADDRESS_TO_CINTOOLS_FOLDER
!include<$(CINTOOLSDIR)\ntlvsb.mak>
especialy that cinlibraries link and opening Microsoft C++ with the *.mak as its base and let Microsoft C++ set up the workspace for you. Be aware that the ADDRESS_TO_CINTOOLS_FOLDER needs to be in the DOS 8 character name format.

Also its good to add to the *.c file:
#include

[Rolf]

"KH" wrote in message
news:506500000005000000F0960000-1027480788000@exchange.ni.com...
> File mapping in LV is easiest using Code Interface Nodes and using the
> Win32 API's in a *.c file. The trick is to create a *.mak file with
> the following information:
> name=CIN_NAME
> type=CIN
> cinlibraries=Kernel32.lib
> CINTOOLSDIR=ADDRESS_TO_CINTOOLS_FOLDER
> !include<$(CINTOOLSDIR)\ntlvsb.mak>
> especialy that cinlibraries link and opening Microsoft C++ with the
> *.mak as its base and let Microsoft C++ set up the workspace for you.
> Be aware that the ADDRESS_TO_CINTOOLS_FOLDER needs to be in the DOS 8
> character name format.
>
> Also its good to add to the *.c file:
> #include

Since you are
using the Windows API this is not a big problem as the
CIN will only work on Win32 anyhow. But in general instead of above
line it would be better to do:

#include "hosttype.h"

This includes the most common include files appropriate for the plattform
you are compiling the CIN for.

Rolf