LabVIEW
Calling Labview from VC++
bshumake@my-deja.com wrote in article <7qh3tk$uv7$1@nnrp1.deja.com>...
> I'm attempting to call Determinant.vi
> (vi.lib\analysis\7linalg.ilb\Determinant.vi) from
> Visual C++. I've actually gotten the
> Determinant.vi to take a matrix that I pass it
> from Visual C++ and return the determinant to me.
> However, to get the determinant.vi to return an
> answer to VC++, Labview has to be running, and
> Determinant.vi has to be manually opened
> from the Functions palette and placed on the block
> diagram panel. Should determinant.vi have to be
> opened before I can use it from VC++?
Yes LabVIEW has to be running. You can achieve this by opening
a reference to the LabVIEW active X Object. Windows then will start
the Active X server for that object, e.g LabVIEW.
Then using the appropriate LabVIEW Active X methods you can load
VIs if you know their absolute file path and afterwards you can call the
VI as you have discovered.
> I'm attempting to call Determinant.vi
> (vi.lib\analysis\7linalg.ilb\Determinant.vi) from
> Visual C++. I've actually gotten the
> Determinant.vi to take a matrix that I pass it
> from Visual C++ and return the determinant to me.
> However, to get the determinant.vi to return an
> answer to VC++, Labview has to be running, and
> Determinant.vi has to be manually opened
> from the Functions palette and placed on the block
> diagram panel. Should determinant.vi have to be
> opened before I can use it from VC++?
Yes LabVIEW has to be running. You can achieve this by opening
a reference to the LabVIEW active X Object. Windows then will start
the Active X server for that object, e.g LabVIEW.
Then using the appropriate LabVIEW Active X methods you can load
VIs if you know their absolute file path and afterwards you can call the
VI as you have discovered.
Sorry for not being able to tell you exactly what you have to do but I have
used Active X only from inside of LabVIEW and someone still needs to
convince me that Active X is something more serious than just having a
few nice demos which work only sometimes. The hassle of distributing
an application which uses Active X seems overwhelming to me and
version conflicts are more common than not.
Do you have an Active X method like Open VI or something like this or
does GetVIReference allow for a complete path? Check out that the
path to the VI you want to open is correct. If you just define the name
LabVIEW won't be able to find the VI as the VI server in LabVIEW
does not search for VIs. It tries to find a VI with that name first in
memory and if i
t isn't there it tries to load a VI from the literal path
you specify. If both fail you get an error back.
bshumake@my-deja.com wrote in article <7qj86j$g81$1@nnrp1.deja.com>...
> What I'm asking is does the vi that I'm using have to be manually opened
> (using LabVIEW), and manually placed in a block diagram window (using
> LabVIEW) in order to use its functionality from Visual C++? I would
> think you could do all of this from VC++ without having to load the vi
> using LabView. My program is designed to start LabView, open the
> Determinant.vi and begin using it. My program does this, but I get an
> exception from the GetVIReference call if I have not opened up LabView
> and the VI that I want to use before running my VC++ program. If I open
> LabView and the VI that I want to use before I run my VC++ program, then
> everything works fine. Has anybody else had this problem?
used Active X only from inside of LabVIEW and someone still needs to
convince me that Active X is something more serious than just having a
few nice demos which work only sometimes. The hassle of distributing
an application which uses Active X seems overwhelming to me and
version conflicts are more common than not.
Do you have an Active X method like Open VI or something like this or
does GetVIReference allow for a complete path? Check out that the
path to the VI you want to open is correct. If you just define the name
LabVIEW won't be able to find the VI as the VI server in LabVIEW
does not search for VIs. It tries to find a VI with that name first in
memory and if i
t isn't there it tries to load a VI from the literal path
you specify. If both fail you get an error back.
bshumake@my-deja.com wrote in article <7qj86j$g81$1@nnrp1.deja.com>...
> What I'm asking is does the vi that I'm using have to be manually opened
> (using LabVIEW), and manually placed in a block diagram window (using
> LabVIEW) in order to use its functionality from Visual C++? I would
> think you could do all of this from VC++ without having to load the vi
> using LabView. My program is designed to start LabView, open the
> Determinant.vi and begin using it. My program does this, but I get an
> exception from the GetVIReference call if I have not opened up LabView
> and the VI that I want to use before running my VC++ program. If I open
> LabView and the VI that I want to use before I run my VC++ program, then
> everything works fine. Has anybody else had this problem?
