Call Library Function Running slow

Hi
I’m using a third party IO board for DAQ experiment. To create a real-time DAQ VI I used the DLL file which’s supplied by the manufacture, I managed to get the VI working to read from the board by using the Call Library function. But the vi running slow, it takes about 10s to get the reading or spot any change, while using Visual basic application any changes are spotted instantly
Any help will be appreciated
Marwan
http://www.geocities.com/marwan_m13/weemee8080.jpg
Attachments:
Project[2].vi ‏42 KB

Just for analysing, where the timeleakage occurs:
Try to measure the execution time of the library function(s). It whould
be interesting, if they realy produce the timeleakage or not.
I modified your project for this (see attachment).
Attachments:
Project[2].vi ‏53 KB

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Passing array to call library function running on VxWorks (cRIO)

Hello,
I am using a cRIO 9012 running VxWorks.
I have a Call library function VI in my application and I want to pass arrays of doubles to this function.
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Here is the source code of my function:
#include "D:\\Programme\\National Instruments\\LabVIEW 8.5\\cintools\\extcode.h"
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The value of in1[0] and out1[0] is always.
When passing no arrays but single values, all is fine. But since my application is more complex than this example, I need to pass arrays.
The block diagram and parameter specification is as shown in the attached screenshots.
I am compiling the source code with the Gcc 6.3 which is available here:
http://zone.ni.com/devzone/cda/tut/p/id/5694
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Or is passing arrays not supported on cRIO?
Maybe the makefile needs to be modified?
Thank you.
Best regards,
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Attachments:
vi.JPG ‏88 KB
parameter.JPG ‏41 KB

I guess I have solved the problem.
The key was to set the parameter "Minimum size" for all function parameters to <None>.
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Window doesn't close wheh Call Library Function Node set to Run in Any Thread

This is a problem regarding Call Library Function Nodes running in the UI thread or any thread.
I have a camera which has its own API supplied as a dll. I have created a set of VI wrappers which each call a function in the dll through a Call Library Function Node.
Initially each CLFN was set to 'Run in the UI thread' (the default).
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This all works fine, and a preview window is opened and images displayed. When I call ICubeSDK_Stop the preview window is closed.
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b) I don't want to put unnecessary stuff in the UI thread
c) my (naive?) understanding is that it is safer to run in any thread
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So, what do I have to do to get the preview window to close properly if I set the CLFN to 'Run in any thread'.
Alternatively, is there a way to close the window programmatically (ie force it to close) after I have called ICube_Stop.
Thanks
DAve

Hi Dave,
The "Run In UI Thread" switches from the thread the VIs currently executing in to the user interface thread. If you select "Run in Any Thread", the Call Library Function Node continues in the currently executing thread. By default, all Call Library Function Nodes run in the User Interface thread.
Before you configure the Call Library Function Node to run in any thread, you have to make sure that the code is thread safe. Code is thread safe when it does not store any global data (e.g. global variables, files on disks, etc.), does not access any hardware, does not make calls to any functions, libraries or drivers that are not thread safe.
Unfortunately, since you said that your DLL accesses hardware, it is not recommended to use "Run in Any Thread." This is probably why you are seeing the crash.
If your preview window gets sent to the back you can programmatically bring it forward. Here is an example of how this can be done: http://decibel.ni.com/content/docs/DOC-4551
If you want to completely close the window down you can do so as described in this link: http://digital.ni.com/public.nsf/allkb/81E9C1441900FFCE8625748F0055DBB0?OpenDocument
I also thought you might find this useful: http://zone.ni.com/devzone/cda/tut/p/id/3009
I hope this helps.
Regards,
Mahdieh G
Applications Engineer
National Instruments UK&Ireland

How can I debug the Call Library Function at run-time

I've written a VI using the CLF to call a DLL which was compiled off-site by another engineer using MSVC. Even though the VI runs without flagging any errors, the VI is not doing what I expect. Is there any way of finding out if the DLL is been called correctly? The first function that is called doesn't return any value, but I think that it should. Does this mean that the DLL is not being called correctly? Note also that the DLL works fine with a JAVA GUI.

Make sure that you are specifying the proper function prototype in the call library function. If you are slightly off the call will not work properly. Ask the offsite engineer to provide you with this data. Another tip is to build the dll with the option to show front panel when called. You can actually popup the dll like you would a subvi. If you design it with test indicators showing on the front panel that is a great way to determine if it is working. Hope this helps.
BJD1613
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Failed to run parallel path when using call library function node in LV2009

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See the image below.
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The lower part contains a call library function node to check the download status, reporting the percentage of downloaded code.
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Regards,
Rob

I've just installed the DETT tool and checked what the different versions of LabView do.
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So it seems there is a 'feature' in LV2009 where modal dialogs are by default not following the preferred execution system set in the VI properties ...
When I change this from "same as caller" into another thread (I used "other 1") then my progress bar works as expected.
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In LV2011, the model VI runs in the caller's thread (preferred execution system set to "follow caller") from start.
Thanks,
Rob

Executable created in LabVIEW 7.1 containing Call Library Function Node runs but creates error when Call Library Function Node is executed

I have created a simplee application that controls a piece of equipment with all control via a supplied dll. Hence, there are a number of Call Library Function Nodes within the code and a modicum of other LabVIEW code. Everything works fine as a LabVIEW application, but when converted to an executable, although the application runs and functions, as soon as any Call Library Function Node is executed, calling from the dll, I get the C++ debug error in the attachment.
Is this something that I can solve from within LabVIEW, or is the problem likely buried in the dll?
Damian
Attachments:
CLFN error.JPG ‏22 KB

Hi Wise,
Try building an executable from a very simple VI that makes one call to the dll. Have you also try using the Call Library Function node on other simple dlls that you know will work?
Regards,
Stanley Hu
National Instruments
Applications Engineering
http://www.ni.com/support

Running Call Library Function Node in UI Thread

Hi there!
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Furthermore I call the same non-thread-safe function twice in my VI, the Call Library Function Node of each being set to "Run in the UI Thread". If I don't enforce the functions to be called in sequence and I change the value of an unrelated VI control while the VI is running (in a While loop), the function generates an error as if it was called by LabVIEW assuming the function w
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Thanks.

Jeremy,
thanks for the confirmation with respect to the greyed out terminal. I
had to find out the meaning of "being right on the money about
something", so thanks for extending my knowledge of the English
language too ... 8-)
Please find the LabVIEW code in attachment. It uses a HP836xx LabVIEW
instrument driver (controlling an RF source) and also calls a C API to
have work done in Mathematica (www.wolfram.com) using MathLink. We
know that the functions which communicate with Mathematica are not
thread safe, so all function calls are set to "Run in UI Thread".
If you look at the block diagram, you find the return value of
LSNAgetEquiTimeStamps() connected to both the greyed out input
terminals of both LSNAgetTimeData().
The VI runs fine, setting the source and collecting data, until I
change the "Power(dBm)" control value. After a few changes, the C API
indicates that the packages which are exchanged with Mathematica are
"out of sequence". The same happens immediately if I indicate that the
functions are thread-safe, by specifying them to be re-entrant. So I
tend to conclude that one way or another the 2nd LSNAgetTimeData() is
executed before the 1st one has finished.
If I eliminate the wire connecting the return value of
LSNAsetEquiTimeStamps() to the lower LSNAgetTimeDat () input terminal
and connect the return value of the upper LSNAgetTimeData() to the
greyed out input terminal of the lower LSNAgetTimeData(), everything
works fine. I can change the value of the "Power(dBm)" control "a
volonte". This is consistent with my assumption above: by changing the
wires I forced the 2nd LSNAgetTimeData() to wait for all inputs to be
available. Because one input is provided by the 1st LSNAgetTimeData(),
I'm sure this one has completed before the 2nd one is invoked.
I cannot explain what is happening. According to the manual, all code
linked to each function node should complete before code linked to
another function node is executed. However, I think I've read
somewhere on the NI website that the UI consists of two threads and
perhaps something goes wrong (internally in LabVIEW ?) when the UI
thread is informed about the fact that the "Power (dBm)" control has
changed.
I don't claim LabVIEW is to blame ... FYI ... the version I'm using is
(the evaluation version) of LabVIEW 7 Express.
Thanks.
Frans.
Attachments:
836xx_LSNA_example_v2.vi ‏99 KB

Execution time for Call Library Function Node

I am experimenting with the Call Library Function Node block in LabVIEW and am curious if it should be running faster than what I'm seeing. For testing purposes, I have compiled and transfered to my RT target the .out file from the KB article http://digital.ni.com/public.nsf/allkb/81D1172E3C28A5E4862575CC0076A230 (I'm using the vxworks 6.1 version). The function in the .out file just multiplies two inputs together, adds a constant, and returns the result. I have put this inside a 1 kHz timed loop with a commanded period of 1 ms and via the Ticks(ms) block and shift registers I calculate the amount of time per loop execution. This process is apparently taking 5 ms per cycle and to me that seems slow. Is that roughly the correct execution time for this kind of setup? I will attach my test .vi file.
What I'm using:
Windows 7
LabVIEW 2009 SP1
NI-cRIO 9024 with NI-RIO 3.4.0
Solved!
Go to Solution.
Attachments:
test DLL.vi ‏31 KB

First off, the way you are doing timing isn't necessarily accurate because you don't know when the tick count VI is being called. For example, if it gets called on one iteration after your call library node executes, and the next iteration it gets called before the CLFN it executes, the subtraction doesn't include the call of the CLFN so you aren't seeing the true time it is taking for the dll to be called.
Where it says "error" on the top left hand corner of your loop. left click and choose previous iteration timing. Also, do you have the ability to choose a 1 Mhz clock? Are you sure it's actually being run on the RT and not on your PC? Running it on the PC would definitely make it difficult to execute at a 1 kHz rate.
CLA, LabVIEW Versions 2010-2013

Passing arrays with Call Library Function does not work after application builder

Calling a DLL with Call Library Function which requires an array of data works correctly in Labview, but after building an exe with application builder, the call no longer works. Dereferecing the pointer in the DLL retuns all 0s and not the actual values.
Solved!
Go to Solution.
Attachments:
TEST.zip ‏28 KB

I did not run your code because it is a little unclear to me what it does.
Two things:
First, is the DLL you are calling the DLL-ified version of PopUpNames.vi? Then the problem is likely that the panel is not being built into the DLL.
When LabView builds an application / dll, it strips the front panel and block diagram from all VIs that it doesn't think need to show a panel at run time. This reduces file size and increases code security. The App Builder's panel inclusion logic can be overridden by Build Specifications -> Source File Settings -> Remove front panel. A better method is to put a property node on a control in a window you want to show marking it "visible"; this is sufficient to tell the App Builder it should keep the panel.
Currently Source File Settings shows "no dependencies" (clearly incorrect---another evil side effect of Express VIs I guess) but if you change the settings as shown below to keep ALL panels, one might hope the App Builder can figure it to keep the panel when it deconstructs the Express VI. (Alternatively convert the Express VI into a regular one.)
A second comment: I am a bit flummoxed at the larger goal here. You are calling LabView DLL from LabView, which doesn't make a lot of sense, so I assume your larger goal is to call LabView from C or vice-versa. In that case be aware that your DLL is x86 (32-bit) but you are passing 64-bit ints as your pointers. In this case it is 32-bit LabView with 32-bit pointers in embedeed in 64-bit containers calling 32-bit LabView with 32-bit pointers in embedeed in 64-bit containers, so it all works, but if your going to call this from C or whatnot you're going to have to follow that same design.
When calling C code the LabView Call Library Function does have a "unsigned pointer-sized integer" data type that always appears to be 64 bits in the dev env but which actually passes a 64 or 32-bit int to the DLL depending on the environment. The "pointer sized int" has to be 64 bits in the "LabView" part of the code because LabView's strong typing requires the data type to be determined at compile time. Casting all pointers to the largest data type in LabView makes it possible to write platform-independent code, but down at the Call Library level you still have to put the right number of bytes on the stack.

Problem in call library function

Hi,
I encountered some problems when using call library function node.
After i select the path in configuration of call library function node, an error message is shown as 1st attachment.
After i tick and the specified path on diagram, link the path name to the node, and run the program. Another error message is shown as 2nd attachment.
Is my dll file got problem? Or i have done a wrong setting?
Here i have attached my dll file.
The dll file is built by Microsoft Visual Studio 2008.
Please kindly advise.
Thank you.
Attachments:
picture1.JPG ‏14 KB
picture2.JPG ‏17 KB
CodeUtil.zip ‏152 KB

TanTan wrote:
Hi,
Is my dll file got problem? Or i have done a wrong setting?
It seems to be compiled for WinCE. Assumed that you have Win2000/XP/Vista/7. Check your MSVC build settings.
Andrey.

Call library function node in a loop

Hello All,
I am currently using a call library function node in a while loop which calls a third party dll to process and recieve some data.
My question is, if I am using this function in a while loop, what exactly happens?
Does the dll get called in each loop iteration, or does it keep the called dll loaded in memory and just pass the values to it to process data?
Also, if the answer to the above question is that it will make calls to the DLL in each iteration, how can we keep it loaded in memory always? I mean, if the DLL is a .NET application DLL, I believe the main .NET application which uses this DLL won't do multiple calls to the dll, rather it will keep it loaded in memory.
Thanks
FraggerFox!
-FraggerFox!
Certified LabVIEW Architect, Certified TestStand Developer
"What you think today is what you live tomorrow"

Hi,
the DLL will stay in memory as long as there is a program running which has not closed (unloaded) the DLL.
Doing repetitive calls to the DLL is irrelevant in this context. LV opens the DLL as soon as needed and will only unload it when there is no VI in memory which has a CLN to that DLL...
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

PDA: Calling library functions - seems to link the stubbed .cpp file instead of the DLL

I'm having trouble developing a Lab View PDA module that calls a DLL built using Visual C++. The DLL functions correctly when called in a non-PDA VI. My issues seem to be with porting to the PDA.
My configuration:
- Lab View 8.5 with the PDA 8.5 module
- Visual Studio 8.0 with the Windows Mobile 6.0 SDK
- ASUS 626 PDA with an Intel PXA70 procesor running Windows Mobile 6 Classic
Following the PPCBatt example code provided with the PDA module, I have:
- used extern "C" to prevent name mangling
- placed the DLL built with the Windows Mobile SDK in the \Windows directory on the PDA
- created a stub Win32 DLL and lib
- created a stubbed cpp file whose functions only return zero
- included the stubbed cpp and lib files in the build spec / source files / additional files
- placed Call Library Function nodes on my PDA VI, selected the function names, set the parameter types
- built and deployed the executable, both with and without debug
When I set the library path property of the Call Library Node, the functions appeared in the function name pulldown, but the parameters did not populate. I had to manually add them and set their types. The help page says they would autopopulate when the function was selected.
I've debugged the VI, and the Library Function Call nodes are being called. It seems the build is linking the code from the stub C file provided in the additional files portion of the source files property page, instead of adding hooks to call the DLL on the PDA. As a test, I changed an output parameter in one of the functions in the stubbed cpp file - the changed value showed in the front panel indicator.
What am I doing wrong?
Dan

Hi Dan,
I'm not sure if I understood you problem fully. When calling external code with LabVIEW PDA, the DLL acts as a stub DLL with the correct function prototypes for the C code that you want to call. Here's a Knowledge Base article that might help explain about calling External Code in LabVIEW PDA.
Regards,
Stanley Hu
National Instruments
Applications Engineering
http://www.ni.com/support

Call library function node with array of clusters using array data pointer

Hello all.
I am writing a LabVIEW wrapper for an existing DLL function.
The function has, as one of its parameters, an array of structs. The struct is very simple, containing two integers. I am using the call library function node to access it.
In Labview I created an array of clusters, where the cluster has two 32-bit integers as its members. So far, so good.
Now I have to pass this in to the Call Library Function Node. Here I am running into trouble.
I have used The topic in LAVA and The topic in the knowledge base as my primary sources of information, though I have read a bunch of forum topics on the subject too.
I do understand that I could write a new function which takes as a parameter a struct with the size as the first member and an array as the second, and I might just do this and have it call the regular function, but I was hoping to do it more simply.
According to the C file which LabVIEW generates for me from the CLFN when I choose "Adapt to Type" and "Array Data Pointer", the prototype it is expecting is:
int32_t myFunc(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
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int borland_dll myFunc(DWORD handle, usint channel,
int FIFOnumber, struct mStruct *data, int numWords, int *actualLoaded, int *actualStartIndex);
This looks like a match to me, but it doesn't work (I get garbage in data). From the topic in LAVA referenced above, I understood that it would work. It does not.
If I cast data to the pointer-to-pointer I get when I generate c code by wiring my struct to a CIN and generating, then I seem to get what I expect. But this seems to work when I choose "pointers to handles" too, and I would expect array data pointer to give a different result.
Is there any way to get this to work directly, or will I have to create a wrapper? (I am currently using LabVIEW 2011, but we have customers using 2009 and 2012, if not other versions as well).
Thank you.
Batya
Solved!
Go to Solution.

OK, here is more detailed information.
I have attached the VI.
This is the code from the "C" file created by right-clicking the CLN and creating a "C" file.
When the parameter in the CLN is set to "array data pointer":
/* Call Library source file */
#include "extcode.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, void data[], int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
When the parameter is "pointers to handles":
/* Call Library source file */
#include "extcode.h"
/* lv_prolog.h and lv_epilog.h set up the correct alignment for LabVIEW data. */
#include "lv_prolog.h"
/* Typedefs */
typedef struct {
int32_t control;
int32_t data;
} TD2;
typedef struct {
int32_t dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
#include "lv_epilog.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
When the parameter is set to "handles by value":
/* Call Library source file */
#include "extcode.h"
/* lv_prolog.h and lv_epilog.h set up the correct alignment for LabVIEW data. */
#include "lv_prolog.h"
/* Typedefs */
typedef struct {
int32_t control;
int32_t data;
} TD2;
typedef struct {
int32_t dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
#include "lv_epilog.h"
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex);
int32_t Load_Transmit_FIFO_RTx(uint32_t handle, uint16_t channel,
int32_t FIFOnumber, TD1Hdl *data, int32_t numWords, int32_t *actualLoaded,
int32_t *actualStartIndex)
/* Insert code here */
As to the DLL function, it is a bit more complicated than I explained above, in the current case. My VI calls the function by this name in one DLL, and that DLL loads a DLL and calls a function (with the same name) in the second DLL, which does the work. (Thanks Rolfk, for helping me with that one some time back!)
Here is the code in the first ("dispatcher") DLL:
int borland_dll Load_Transmit_FIFO_RTx(DWORD handle, usint channel, int FIFOnumber, struct FIFO_DATA_CONTROL *data, int numWords, int *actualLoaded, int *actualStartIndex)
t_DispatchTable *pDispatchTable = (t_DispatchTable *) handle;
int retStat = 0;
retStat = mCheckDispatchTable(pDispatchTable);
if (retStat < 0)
return retStat;
if (pDispatchTable->pLoad_Transmit_FIFO_RTx == NULL)
return edispatchercantfindfunction;
return pDispatchTable->pLoad_Transmit_FIFO_RTx(pDispatchTable->handlertx, channel, FIFOnumber, data, numWords, actualLoaded, actualStartIndex);
borland_dll is just "__declspec(dllexport)"
The current code in the DLL that does the work is:
// TEMP
typedef struct {
int control;
int data;
} TD2;
typedef struct {
int dimSize;
TD2 data[1];
} TD1;
typedef TD1 **TD1Hdl;
// END TEMP
int borland_dll Load_Transmit_FIFO_RTx(int handlertx, usint channel, int FIFOnumber, struct FIFO_DATA_CONTROL *data, int numWords, int *actualLoaded, int *actualStartIndex){
struct TRANSMIT_FIFO *ptxFIFO; //pointer to transmit FIFO structure
usint *pFIFOlist; //pointer to array of FIFO pointers to FIFO structures
int FIFOentry, numLoaded;
usint *lclData;
usint nextEntryToTransmit;
// TEMP
FILE *pFile;
int i;
TD1** ppTD = (TD1**) data;
TD1 *pTD = *ppTD;
pFile = fopen("LoadFIFOLog.txt", "w");
fprintf(pFile, "Starting Load FIFO with %d data words, data pointer 0x%x, with the following data&colon; \n", numWords, data);
for (i = 0; i < numWords; i++) {
fprintf(pFile, "%d: control--0x%x, data--0x%x \n", i, data[i].control, data[i].data);
fflush(pFile);
fprintf(pFile, "OK, using CIN generated structures: dimSize %d, with the following data&colon; \n", pTD->dimSize);
for (i = 0; i < numWords; i++) {
fprintf(pFile, "%d: control--0x%x, data--0x%x \n", i, pTD->data[i].control, pTD->data[i].data);
fflush(pFile);
// END TEMP
if ((handlertx) <0 || (handlertx >= NUMCARDS)) return ebadhandle;
if (cardrtx[handlertx].allocated != 1) return ebadhandle;
pFIFOlist = (usint *) (cardrtx[handlertx].segaddr + cardrtx[handlertx].glob->dpchn[channel].tr_stk_ptr);
pFIFOlist += FIFOnumber;
ptxFIFO = (struct TRANSMIT_FIFO *)(cardrtx[handlertx].segaddr + *pFIFOlist);
//use local copy of ptxFIFO->nextEntryToTransmit to simplify algorithm
nextEntryToTransmit = ptxFIFO->nextEntryToTransmit;
//on entering this routine nextEntryToLoad is set to the entry following the last entry loaded
//this is what we need to load now unless it's at the end of the FIFO in which case we need to wrap around
if ( ptxFIFO->nextEntryToLoad >= ptxFIFO->numEntries)
*actualStartIndex = 0;
else
*actualStartIndex = ptxFIFO->nextEntryToLoad;
//if nextEntryToLoad points to the last entry in the FIFO and nextEntryToTransmit points to the first, the FIFO is full
//also if nextEntryToLoad == nextEntryToTransmit the FIFO is full and we exit without loading anything
if (( (( ptxFIFO->nextEntryToLoad >= ptxFIFO->numEntries) && (nextEntryToTransmit == 0)) ||
( ptxFIFO->nextEntryToLoad == nextEntryToTransmit)) && (ptxFIFO->nextEntryToLoad != INITIAL_ENTRY)){
*actualLoaded = 0; //FIFO is full already, we can't add anything
return 0; //this is not a failure, we just have nothing to do, this is indicated in actualLoaded
numLoaded = 0;
lclData = (usint *)data; //must use 16 bit writes to the module
//conditions are dealt with inside the for loop rather than in the for statement itself
for (FIFOentry = *actualStartIndex; ; FIFOentry++) {
//if we reached the end of the FIFO
//if the module is about to transmit the first element of the FIFO, the FIFO is full and we're done
//OR if the module is about to transmit the element we're about to fill in, we're done - the
//exception is if this is the first element we're filling in which means the FIFO is empty
if ((( FIFOentry >= ptxFIFO->numEntries) && (nextEntryToTransmit == 0)) ||
((FIFOentry == nextEntryToTransmit) && (FIFOentry != *actualStartIndex) )){
*actualLoaded = numLoaded;
//set nextEntryToLoad to the end of the FIFO, we'll set it to the beginning next time
//this allows us to distinguish between full and empty: nextEntryToLoad == nextEntryToTransmit means empty
ptxFIFO->nextEntryToLoad = FIFOentry;
return 0;
//we reached the end but can continue loading from the top of the FIFO
if ( FIFOentry >= ptxFIFO->numEntries)
FIFOentry = 0;
//load the control word
ptxFIFO->FifoData[FIFOentry * 3] = *lclData++;
//skip the high of the control word, the module only has a 16 bit field for control
lclData++;
//now put in the data
ptxFIFO->FifoData[(FIFOentry * 3) + 2] = *lclData++;
ptxFIFO->FifoData[(FIFOentry * 3) + 1] = *lclData++;
numLoaded++;
//we're done because we loaded everything the user asked for
if (numLoaded >= numWords) {
*actualLoaded = numLoaded;
ptxFIFO->nextEntryToLoad = FIFOentry+1;
return 0;
//if we reached here, we're done because the FIFO is full
*actualLoaded = numLoaded;
ptxFIFO->nextEntryToLoad = FIFOentry;
fclose (pFile);
return 0;
As you can see, I added a temporary diagnostic with the structures that were created in the "Handles by value" case, and print out the data. I see what is expected, whichever of the options I pick in the CLN!
I understood (from the information in the two links I mentioned in my original post, and from the name of the option itself) that "array data pointer" should pass the array of data itself, without the dimSize field. But that does not seem to be what is happening.
Batya
Attachments:
ExcM4k Load Transmit FIFO.vi ‏15 KB

Strange problem of calling library function node in labview 2010 and 2011

one year ago,I develop a program to usb device data and it works well,in labview 8.6 or 2009(win xp).Recently, When I test
the program in labview 2010 and labview 2011(win xp).,the program always crash immediately.I check the program and find main
problem is in call library function node. In my program,I use labview 2009 library for the USBExpress driver for
Silicon Labs USB MCU's from:https://decibel.ni.com/content/docs/DOC-9522,for example, 2 functions SI_OPEN and SI_READ
can not work well.
the header definition of SI_OPEN and SI_READ is:
SI_STATUS WINAPI SI_Open(
DWORD dwDevice,
HANDLE* cyHandle
SI_STATUS WINAPI SI_Read(
HANDLE cyHandle,
LPVOID lpBuffer,
DWORD dwBytesToRead,
LPDWORD lpdwBytesReturned,
OVERLAPPED* o = NULL
the SI_STATUS is equivalent to int type.
orignally, for HANDLE * in SI_Open, the parameter type in call library function node is numeric, data format is unsigned 32 bit integer ,and pass pointer to value.
for HANDLE in SI_Read, the parameter type in call library function node is numeric, data format is unsigned 32 bit integer ,and pass value.The program works well in labview 8.6&2009,however,crash in labview 2010 &2011.
later,I debug the program, for HANDLE *, I choose parameter type in call library function node as adapt to type, data format is point to Handles.for HANDLE, I choose parameter type in call library function node as adapt to type, data format is Handles by Value.Crash not happend in labview 2010&2011,however,it cannot read any data from from USB device correctly as before.I can not find the reason.
Dear friends,I need your help to answer the problem. Thank you.

Based on the help page it looks like it should execute asynchronously.
The thing in the description that leads me to believe they execute asynchronously is that you can configure the library to run as a multi-threaded operation.
Please take a look here to see the difference between synchronous and asynchronous execution.
Since the code even has the ability to be multi-threaded, you can consider it as running in parallel to your other code.
Any data returned is passed to the thread that called that function.
Cory K

Call library function inside a conditional disable bug

i'm trying to call a function in a dll using the call library function inside a conditional disable structure.
one of the parameters is a pointer to a C structure.
here is the prototype:
short in myfunction(short in DevNum, void *pMetrics);
outside of the conditional disable, LabVIEW allows me to wire the pMetrics parameter to a cluster.
if i put the function inside the conditional disable, LabVIEW doesn't allow me to wire it.
as a workaround, i put the cluster inside the conditional disable as well.
any ideas?

Simply create a constant of the cluster and and put it outside the disable structure. Wire this constant to all inputs (left side terminal) of the Call Library Node. A Call Library Node (CLN) set to Adapt to Type does need a valid datatype to adapt too. This works from the outside side (right side terminal) of the CLN only if the according indicator is inside the same data structure. In older LabVIEW versions you actually had to always define the left side by wiring a constant or a dummy control to it.
This has to do with the algorithme that evaluates datatypes along wires. Making that algorithme go backwards (against the natural dataflow) inside one subdiagram without causing circular references or similar is already a challange. Doing that across diagram boundaries (case, disable, loop, etc. structures) is basically impossible without causing the entire edit operation to get very slow.
Message Edited by rolfk on 10-20-2009 08:28 AM
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Call Library Function Running slow

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