Despite indicating to the path, still have manually pointing DLL every time LV works using the library function node call

Similar Questions

• When I use the library function node call in real time, is loaded only once for all or load the DLL whenever it is called?

  When I use the library function node call in real time, is loaded only once for all or load the DLL every time when it is called?

  I have a critical application in real time, in which I use a piece of DLL function developed in C++.  It is ok?  Make sure any senior developer?

  Thank you in advance.

  The user interface thread is the thread that is used to update the user interface. It's slow. And it's supposed to be that way because humans are slow.

  The call library function node can be configured as this thread to use in the configuration for it dialog box. Please visit the LabVIEW documentation on how to do this.

• Exception in the external code called by calling the library function node problem

  Hello, I am a complete newbie in LabVIEW and need help. I have run tests of reliability and get this error about 2000 cycles. The code sends the digital output of a cylinder which operates the actuator downwards, he reads a signal of the thing I'm testing. Then there is a signal to then drive the actuator to the top and repeat. After about 2000 cycles, I get the error:

  [LABVIEW: an exception occurred in the external code that is called by a node call library feature.] It might have corrupted the memory of LabViews. Save all work to a new location and restart LabView. VI "Footswitch.vi" was arrested at the node 0 x 0 of the Subvi "DAQmx Start Task.vi 7"]. "

  I created this code without any prior knowledge of LabView, so I know it's not good, but it does not have (somehow). Any help would be greatly appreciated. Thanks in advance. I am also attaching the VI.

  cstemm,

  There are a few obvious errors in the code that must be addressed.  First of all, I'm not sure how your code even survived 2000 cycles, you have a Boolean value enter these while loops:

  

  What happens if you read a false? The curls will be stuck in an infinite loop... as the value read from the tunnel will never change, and the stop condition will always be "false".   I think that what you do... was keep reading the numerical value until it is true, so it's what needs to be in a while loop.

  Now, the problem you are experiencing is most likely a result of mass overload of start/stop tasks.  For these digital readings, simply start the task once and stop the task once. Run the start task until your main loop work... reference col in the task and read when you want to. Then, when the main loop is completed, go to this thread of task outside the while loop to clear tasks and stop.

  Programming paradigm is generally (there are exceptions):

  Initialize (startup tasks, the initial set of controls, etc.) -> the main loop (here, most of the code is readings/writings/calculations)-> References(stop tasks, clear data, close any open file references) close

  You don't do any reads buffered of digital lines, so no need to ever stop or restart the task, it gives you just a value whenever you call playback vi.

• Disable the use of structure in a lead time library function node increases

  I found that if I use a stureture disable to disable one of the outputs of a library function node call, the run time will be greatly increased. Can someone explain this?

  

  You can read this thread and benchmarking, I did there.

  Turn off debugging and check if the loss of performance you MENTION (but not quantified) is still there.

• VI Analyzer: the wire under the test object fails with call library function nodes

  Hello

  If I have a knot of function call with an ErrorIn and an ErrorOut library, the VI thread Test Analyzer "Thread under object" always fails with two hits in a library function node call.

  Double click to the salient facts occurrence lines error related to the call... node.

  The test fails, if the error lines are not connected.

  Thank you!

  H

  Sorry, created the CAR number is #208992.

  Kind regards

  Michael

• I have subscribed to the monthly subscription to Photoshop CC2014. It is always my trial subscription has expired and I have to sign in every time. How can I stop this?

  I signed up for Photoshop CC2014 on a monthly subscription and I am still getting a message that my trial version expired one that I have to sign in every time. How can I stop this?

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• What is the right way to specify the location of the shared library in an a .lvlib function call library function node?

  I'll have a bit of a problem with how to specify the location of library shared in a call library function node it is a VI that is part of a library of LV. Here's a little background which may help.

  I do a lot of measures using spectrometers photo from several manufacturers.  Someone in my company developed a C DLL library, which provides a simple API for all the different spectrometers. To facilitate this DLL to use in LabVIEW, I wrote a .lvlib that wraps all the functions.  When I want to use the API, I simply include the .lvlib file in my project that allows me to drag and drop the wrapper s VI on my block diagram. When I created the .lvlib of VI, I specified the path in the call library node. /. * so it will always look in the local application to the DLL directory when I run.

  The problem is, when I load demand, LabVIEW you asks for the location of the DLL even if it's just there in the local directory! I tried to put copies of the DLL in the directory with the .lvlib, but he still refuses to find the DLL loading.  What I am doing wrong?

  You should in this simple case enter the full path to the DLL by navigating to it. If the DLL is on the same volume/drive that the VI containing the call library node LabVIEW will be internally store the relative path from the VI to the DLL (but still show the absolute path). If you move the DLL and screw together (so the relative location of the DLL to the VI remains the same) LabVIEW will always find the DLL.

  I don't think that the lvlib would add nothing to that.

• Loading of the DLL string using the Code Library function node

  I experience now with the element of Code Library function node... what I wanted to do are, for example, I have compiled a. DLL file... which has a function that returns the pointer to string... function looks like:

  / * This function returns a pointer to the character string * /.

  char * pchar (int n)

  {

  char * str [] = {"error", "String1" and "Word2", "3"};

  Return ((n! = 1) & (n! = 2) & (n! = 3))? Str [0]: str [n];

  }

  but when I load into LabView DLL, a part of the chain on the screens to Panel frontal trash... any ideas why?

  p.s. when I do even with integer values... say my job is like int x = 5; Return x; and then I load in LabView to the digital indicator... it works great!

  So any ideas?

  thanx

  Cyrax says:

  I experience now with the element of Code Library function node... what I wanted to do are, for example, I have compiled a. DLL file... which has a function that returns the pointer to string... function looks like:

  / * This function returns a pointer to the character string * /.

  char * pchar (int n)

  {

  char * str [] = {"error", "String1" and "Word2", "3"};

  Return ((n! = 1) & (n! = 2) & (n! = 3))? Str [0]: str [n];

  }

  but when I load into LabView DLL, a part of the chain on the screens to Panel frontal trash... any ideas why?

  p.s. when I do even with integer values... say my job is like int x = 5; Return x; and then I load in LabView to the digital indicator... it works great!

  So any ideas?

  thanx

  You cannot return a pointer to the data stored on the stack. At the time when the function returns, the stack is reset to the State before the call to the function and in a multithreaded as LabVIEW environment probably long reused for other things when LabVIEW gets around to actually copy the returned pointer data.

  Since it is a read-only variable, you could create a permanent memory for string storage by declaring your variable static. This will create a memory area allocated globally for the string data (and also cause a compile error when you try to write in this area somewhere in your code, which is a good thing).

• How does the library function call Labview? Can I emulate using C++?

  Hi all. I recently finished writing a dll CUDA for LabView, and now I'm in the steps of optimization of code, memory management, etc. BUT since my code depends on the entries of Labview (lots of data under types of specific data as table manages and Clusters labview) I can't use the CUDA Profiler or the Profiler VC ++ on the DLL. What I intend to do runs labview and then out of all data entry for the DLL in a binary file and then add an additional function in my code that will read in the binary file, allocate and assign variables to their respective positions, and then call the specific DLL function in Labview. In the end, this miniature function will act as the library function call to my specific group of data entries.

  In any case, I started to make this purchase all my data entry of cluster and it comes out in a binary file. And then I started the initialization of the handles of labview, allocating memory and begins to write the binary data in the memory and it works for integers (ints), floats, etc., but I'm confused on how it works with table handles!

  Some examples of code:

  Sets the Handle for table 1 d for INT
  
  typedef struct {}
  
  	int length;
  
  	int val [1];
  
  		to access the value in a row-online val [Online]
  
  } Array1dInt, * Array1dIntHandle;
  
  int main()
  
  {
  
  	Array1dIntHandle x = new Array1dInt *;
  
  	(* x) = new Array1dInt;
  ifstream file ('TESTDATAIN.dat', ios: in | ios::binary);
  If (file.is_open ())
  
  	{
  
  		file ((char *) &(*x)-> length, sizeof;)
  
  		file ((char *) &(*x)-> val [0], sizeof (int) *(*x)-> length);
  LabviewSpecificFunction (x);
  
  		leader. Close();
  
  	} else
  
  	{
  
  		< "file="" did="" not="" open!"=""><>
  
  	}
  
  	return 0;
  
  }
  __declspec(dllexport) LabviewSpecificFunction (Array1dIntHandle x)
  
  {
  
  ...
  
  }

  However, my program crashes when the table is nominally big, and it is expected, because if we look at the Array1dHandle, it has allocated only enough memory to 1 item of value! YET, somehow, in its magical and mysterious labview is capable of making val [1] be val [HOWEVERMANYYOUWANT], even if C++ 101 says that val [1] is a constant pointer, and even if I dynamically allocated memory another somwhere, I would never be able to put these data in this round!

  Can you explain, or maybe even write example on how I can fool my program into thinking that the binary code comes from labview, so I can then run my program independent of allowing me to profile the functions inside labview?

  I hope that this question is clear and my sample code is also clear, but I'm happy to answer any questions that relate to this.

  Thank you all!

  I think that I thought about it.

  Array1dIntHandle x = new Array1dInt *;
  int tempsize;
  
  file ((char *) & tempsize, sizeof;)
  
  (* x) = (Array1dInt *) malloc (sizeof (int) + sizeof (int) * tempsize);
  
  (* x)-> length = tempsize;
  
  file ((char *) &(*x)-> val [0], sizeof (int) *(*x)-> length);

  Well enough, you will need to make the handle, and then make a new Array1dInt * for him, then read in the length of the array in a temporary variable. Then use this information to then malloc memoery quantity you need for the table and pass this place on the handle. Now the handle will point to the size of the memory and you will be able to access the memory in the format, you've done the handle. Badabing badaboom

• I have xp sp3, and every time I start internet explorer 8, it opens closes again on his own why? HELP PLZ?

  I have xp sp3, and every time I start internet explorer 8, it opens closes again on his own why? HELP PLZ?

  See if this article solves your problem:

  "Internet Explorer opens, flashes and closes immediately when you start"
   <>http://support.Microsoft.com/kb/967896 >

  HTH,
  JW

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  Go back, is there a way to set up where when starting, the main screen shows and not the last used screen?

  Thanks to all who can help this old computer old unwhiz.

  Go the Prefs system/users and groups, release at the bottom left then open the Options of connection and use the top menu drop down for an automatic connection.

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• Memory from the Flushing call library function node

  I use the function call library (COLD LAKE) node to load some dll dynamically in a same vi.

  I use a loop for to send the DLL files or a table to COLD LAKE to load the different dll.

  For the first iteration, the COLD LAKE works very well, but for the second iteration and so on can not replace the output variable, and continue to repeat the result of the first iteration.

  Is there anyway to clear the memory of COLD LAKE, so that I will get the correct result for DLL 2nd and so on?

  I understand your message, you have different dll, which returns an array of LabVIEW.

  This table can be of different sizes according to the DLL you are calling.

  I think that you are having a general misunderstand about LV memory management. I think that your comments refer to the data space LV has allocated for the table, this has nothing to do with the DLL itself said!

  LV works memory about conservative. So if you allocated a data space, execution of a new of the same VI will try to reuse this dataspace. So the tables are not released if the VI will slow.

  That being said, the table itself will not reduce its size.

  The only question I have on this: you still have all the available values? If the new call returns the three values (out of 33), is the rest 30 items "the old value"?

  For ANSI C dll - it is common that the DLL also returns a scalar value "arraysize". If you got that, you can use the Array subset function to retrieve valid values.

  Norbert

• Call the library function does not find the DLL in the directory where are my LLBs

  I'm using LabVIEW 8.6.  I have a set of screws in several LLBs.  All LLBs located in a directory.  Most of my screws is wrappers for the functions in a DLL.  I was told to put my DLL in the directory where are the LLBs, and apparently this is how the previous programmer has worked (using an earlier version of LabView).

  In the configuration of the library call, I've specified .dll without path.  (This is how we want our screws are an API that will integrate other programmers, so I don't know where they put things and I can't use absolute paths).

  When I insert the VIs in LabVIEW, LabVIEW can not find the DLL and wonder of spotted.  It's just that here in the directory with the LLBs and when I double click on it, everything works fine.  However my absolute path to the DLL now appears in the library to call configuration, and we don't want that.

  Does anyone know how to make this work?  I guess the location of the screw (or LLBs, in this case) should be the current directory and thus Windows search there for the DLL.  However, it seems that this is not the case (in the least, in the latest version of LabVIEW).

  Thank you.

  Batya

  Well someone using your library should not have to dig into your screws and do it all on his own. Instead your library must wrap that and hide disorders it altogether.

  The cluster of error has been added when the dynamic path option has been added. It is not useful hide this error output, so it's always there. As well as the dynamic path, there was the improved error handling added the CLN. One of them is that the level of verification when calling function errors (exception handling) can be specified. I guess that some of these options may generate an error code instead of bring up a dialog box, as they did before and that the output of error code can be useful even in the case of static calls.

  As to what you want to do, I would have long managed that with a DLL that has essentially the same functions as your other wrapper DLLs and an initiliasation function that returns a pointer to a structure of functional distribution based on the actual DLL you want to call. Quite like what an object-oriented function dispatch table is. Then, when your interface initilising you call initialize function and specify the device interface/type that you want to use and after that all other functions take a pointer extra function parameter expedition as the first parameter, in addition to the parameters of the real function. This dispatch function pointer would be just a pointer to a structure that contains the table of function for this interface pointers and the sake of LabVIEW would simply be an integer of size pointer.

  The wrapper function then checks the pointer structure validity send feature and call the actual function with the remaining parameters. It is a C programming and may require a planning and desigining the different interfaces to facilitate this kind of technique of the expedition, but it will certainly pay to long-term and make your library even can be used in previous versions of LabVIEW, so that VB etc. without delicate dynamic loading in the level high, programming environment.

  Rolf Kalbermatter

• How to implement a callback to the help function call library function node in LabView?

  I try to call a fuction from a SDK.dll library by using the node call library feature. The SDK has been provided to

  me and I don't have the source code, just the .dll and .h files.

  The SdkSetPropertyEventHandler function has a function of recall as one of its parameters. How to apply the

  callback using the NSI node? I'm a good programmer LabView but this is my first time using the library to call

  Function node. I read all the info I can find on the web site of NOR and the discussion Forum, but can not understand

  This one out. I'm using LabView 8.6.

  The deacribes SDK.h function as:

  Function: SdkSetPropertyEventHandler

  (SdkSetPropertyEventHandler) SdkError SDKAPI
  SdkCameraRef inCameraRef,
  SdkPropertyEvent inEvnet,
  SdkPropertyEventHandler inPropertyEventHandler,
  SdkVoid * context);

  //
  Description:
  Registers a callback function to receive the status
  change the notification events for the States of property on a camera.
  //
  Parameters:
  In: inCameraRef - designate the object camera.
  inEvent - designated one or all the events will be completed.
  inPropertyEventHandler - designate the pointer to the callback
  function to receive the camera property-related events.
  inContext - designated application information must be passed
  way to the callback function. All the data necessary to
  your application can be passed.
  Output: no
  //
  Returns: A sdk errors.
  -----------------------------------------------------------------------------*/

  A separate header called SDKTypes.h file contains the following data:

  typedef SdkUInt32 SdkPropertyEvent;
  typedef SdkUInt32 SdkPropertyID;
  typedef void SdkVoid;

  typedef struct __SdkObject * SdkBaseRef;
  typedef SdkBaseRef SdkCameraRef;

  /*-----------------------------------------------------------------------------
  SdkPropertyEventHandler
  -----------------------------------------------------------------------------*/
  typedef SdkError (SDKCALLBACK * SdkPropertyEventHandler))
  SdkPropertyEvent inEvent,
  SdkPropertyID inPropertyID,
  SdkUInt32 inParam,
  SdkVoid * context);

  Thanks for your help.
  Alejandro

  Andrew_E wrote:

  Hi Rolfk,

  You are absolutely right. This article describes what you were talking about? I'm just trying to get as much information as possible on this thread if the solution is easier to find for the future. Thank you.

  Yes, but I find the idea of using .net to call a LabVIEW VI as callback function C a bit as using a roll of Steam ironing your pants. Why do it? Well the steamroller has extra security guards that make it less likely that you'll break your pants in the process, but it's not elegant IMHO.

  Write a C DLL that translates between a C callback and a user event LabVIEW using the PostLVUserEvent() of the interface of the kernel to run LabVIEW function seems so eleganter for me. Yes, it's a bit of programming in C, but good!

  Rolf Kalbermatter

• Name of the function mutilated in the call library function node

  Hello

  I am change an existing wrapper LabView project, I added a function, and even if I used the same settings of export, it is used for all other functions, the new function name appears truncated.

  The code of the DLL:

  #ifdef OS_WINDOWS
  
  # define exportspec extern "C" __declspec (dllexport)
  
  #else
  
  Exportspec int S7API lv_Srv_RegEvents (S7Object, LVUserEventRef Server * EventRef, PSrvEvent EventData);
  

  The library Call dialog box:

  

  Even if the function itself is empty, LabView still triggers the corruption of General memory error.

  Help, please.

  Oh me,.

  the S7API definition is lying __stdcall

  

  now, it works fine...