Call a function in a function?

Similar Questions

• 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

• Call library function node

  When using a call library function node, and the program came out, I get an error "has encountered a problem and needs to close" having to do with ntdll.  It does not stop the program from running properly, but it's annoying.  Any ideas?

  You should NOT specify the full path to a DLL system in the configuration dial the node of the library. This mess something in the newer versions of Windows. Instead just enter the name of the DLL only. It is sort of a bug in LabVIEW not automatically detect the system paths and shorten the path accordingly in itself, but this is how things have been for a long time and you just need to be a little careful.

  Also the return value must be really set up to be an integer of size of pointer, since a HANDFUL is really a pointer under Windows and that the first parameter is also better configured as such. The way you did works very well for LabVIEW 32 Bit but will misbehave in LabVIEW 64 Bit.

• 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.

• Crash when moving from a structure in a call library function node

  I am trying to use a type of Fortran (which I think is similar to a struct) in a LabVIEW call library function node.  I read a few remedies to this topic, but I'm not quite sure if I need to add the name of the parameter list of the node structure.  Now, when I run my VI it closed just LabVIEW entirely with no message.  I've attached the VI that I use and code source fortran, which compiles in my .dll.

  Any help is appreciated.

  Do you know if Fortran passes parameters by value or by reference?  I never used it.  A very quick search on the internet gives to think that the parameters must be passed by reference.  If this is the case, then you must pass the entire cluster as the parameter single, similar to Fortran statement.  You must also change the order of cluster to match the order in the Fortran statement.  Try the attached VI.

• Call the function in LabView from a DLL, and then access the global variable of DLL

  I've created a DLL in LabWindows with a function and structure.  I want to call the function from LabView and then access the overall structure.  I am able to call the function in the DLL with a "call library function node" and has access to the return value, but I can't understand how to access the overall structure.  The structure is declared in the header DLL with __declspec (dllimport) struct parameters file.

  Is it possible to access this structure without using the library of network variables?

  My guess is that you need two bytes of padding after "in_out" and another to two bytes of padding after "anin."  The reason being that ints are 4 bytes, and most of them C compilers will align on 4-byte boundaries.  The struct will naturally start to such a limit (in fact, in Windows, it will probably start to an 8 byte boundary).  If you then count bytes in your structure, you are 70 byte after "in_out."  70 is not divisible by 4, so you need 2 bytes more to reach the next 4 byte boundary.  You can also you could reorganize your struct so that "anin" follows "in_out" and this is probably the best option if it won't cause you other problems.

  Unlike most C compilers, LabVIEW compressed structures as closely as possible, without filling.  I don't know enough about the history of LabVIEW and internal parts to explain the reasons and to do this performance penalty, but, as choice of LabVIEW "endianness", it is probably a remnant of the first versions of LabVIEW that were running on the Mac.

  If for some reason you want to force your C struct to match package LabVIEW, you can use the #pragma pack (x) directive, but I wouldn't recommend that here because you can control the C and LabVIEW.

  EDIT: in the cases where it was not clear, add padding to your cluster of LabVIEW, insert appropriate size or items at the place desired in the cluster.

• help with call library function node

  I have problem with node function call library that I try to use velleman k8061 dll file to get this working labview

  all I'm trying to get the same problem

  but I chose one to explain it

  SetDigitalChannel
  Syntax
  PROCEDURE SetDigitalChannel (CardAddress: Longint;) Channel: Longint);
  Parameters
  CardAddress: The address of the previously opened card.
  Channel: Value between 1 and 8, which corresponds to the output channel to be resolved.
  Description
  The selected digital output channel is activated.
  Example of
  BEGIN
  SetDigitalChannel (0, 1);

  now, when I try to call the function of library in k8061.dll node and set up 2 a card address and one for the channel

  address of card type: type numeric & statistics: signed 32 bit intger

  channel type: numeric type & data: signed 32 bit intger

  function prototype

  void setdigitalchannel (int32_t, intg32_t channel address);

  I also configure error call library function node checking up

  now that I run it, I get error 1517 produced and tell me this mismatch between the calling conventions?

  problem solved

  thanx

• How to identify which switch in the Panel called the function?

  Here I have some 192 switches and 192 leds corresponding to each switch,

  If a switch is on(say 10th) consequence (10th) led should light up.

  I want to use the same function for all pairs of led switch.

  all I could do was to check the switch in a loop and then set the individual leads, but I find it very little effective way to do it.

  int switchOnOff (int, int int event control panel CVICALLBACK,
  void * callbackData, int eventData1, int eventData2) is the function.

  None of these arguments I can use it to extract what (the unique id for this turnout) switch called the function so that I can pass corresponding led glow?

  It occurred to me now that the table is not necessary at all: you can simply assign to each switch the corresponding ID led the callbackData, so that the code is even simpler than my previous:

  // At panel load:
  SetCtrlAttribute (panelHandle, PANEL_SWITCH1, ATTR_CALLBACK_DATA, (void *)PANEL_LED1);
  ...
  SetCtrlAttribute (panelHandle, PANEL_SWITCH192, ATTR_CALLBACK_DATA, (void *)PANEL_LED192);
  
  // In the control callback
  GetCtrlVal (panel, control, &sts);
  SetCtrlVal (panel, (int)callbackData, sts);
  

  To answer your last question, "Management Board" means immediately after the call to LoadPanel.

• call library function node - function not found

  When you create a DLL, I get a error Labview "node"LabviewReceiverDLL.dll:readDataJ1939Data "function not found." call library function Everything looks good to me and cela used to work, even if I changed computers since then.

  This is the beginning of my C++ code just to show my name of the function. I've also attached the function of the library calls window to show my setup.

  Thanks in advance for your help.

  #include "StdAfx.h"

  #include

  / * Call library source file * /.

  extern "C" __declspec (dllexport) unsignedint readDataJ1939Data (unsignedint, unsignedint, unsignedchar, unsignedchar * canData, unsignedchar path);

  unsigned int readDataJ1939Data (ulTimeStamp, ulIdentifier, unsignedchar uiDataCount, unsigned char unsignedint unsignedint * canData, constchar path)

  {

  I've recreated the DLL and Labview library node call and now it works.

• call library function node to paste files

  Hello, I use the call library function node to paste the text to and from the Clipboard and works well.  Now, I'm trying to figure out how to paste a file from the windows file Explorer.  So if I highlights a file in the Windows File Explorer and press Ctrl-C, how can I use the library function node spit a file path?  It would be even better if I could highlight a bunch of files and then paste a table of paths, but that can wait.  Also, I use a Listbox MC, so I can't use drag-and - event trigger move a control path of the file.

  Also, I use WinXP and LV 7.1.

  Thank you

  Pat

  UPDATE

  I had little time to play with it and really out of curiosity on my part that I have whipped up a simple example to drag and drop from the Explorer in LabVIEW. I wrote the code in 7.1, but I have 7.1 on a virtual machine, and the DragQueryFiles did not work. I don't know if it was due to the fact that I was running on a virtual machine. I did, however, run the code in 8.2 and it works correctly. 8.2, I was able to drag a bunch of files in front of the VI, and the string table fills with file names. I am especially to see if it might work for you. You will need to get the Windows Message Queue library. Simply place the library in the same folder where you unzip the attached file.

• Connection of several call library function node

  

  First of all, I apologize if some of these issues are pretty basic. For my work, I have been teaching myself LabVIEW (using one of the books) for the last two months, in addition to a course of semesters of C++ software development. I have flowed through a few examples from the book and have searched these forums + google search, but I found the contradictory and confusing information on how to manage the C string data.

  I have attached a photo of the block diagram, the real VI and a manual describing the .dll file I'll call you. My real application is more complicated than what I've built here (I installed a trial version free at home, since I can't bring my lab computers files due to their having no do not have access to the internet...) There install everything for us, but it's a side story!), but deals with execution other than that, as I have the VI wrapped around an imposing event that runs based on which side a user presses the button, messages pop up additional user, etc..

  In the end, I'll implement a program which allows a user presses a single button that sends a bunch of instructions to an instrument, where requested orders have been compiled by the society of the instrument in a couple of .dll files. The instrument itself be held the certain function specifications, so there is not much need to worry to get somewhere, out string parameters to be stored, and there is no reception data of the instrument: it simply distributes liquid charges based on what parameters I pass to it. Given the same internet connection problems, I have to wait a few weeks for my IT team installed a decompiler of .dll file on the computer that has installed LabVIEW so that I hope that I can directly import the header file in the Import Wizard. I worked out of their manual without even being able to look in the .dll file (which may be more documentation), and they do not have the more detailed documentation on their data types (even if maybe these data types are public knowledge, and I'm just missing something). I went ahead and copied + pasted some of their function prototypes + example code pages 16 and 17 of the provided pdf (it looks like to me a C calling convention):

  'Functions of the DLL to talk to the PiezoElectronics.

  Public Function declare bfx_piezo_OpenPort Lib "bfx_piezocontrol.dll" (ByVal portname As String) As Integer

  Public Function declare bfx_piezo_ClosePort Lib "bfx_piezocontrol.dll" () As Integer

  Public Function declare bfx_piezo_ConfigurePiezo Lib "bfx_piezocontrol.dll" (ByVal ability As Double, ByVal VoltagePerStroke As Double) As Integer

  Public Function declare bfx_piezo_SetupPiezo Lib "bfx_piezocontrol.dll" (ByVal StrokeLength As Double, ByVal DownStrokeVelocity As Double, ByVal HoldTime As Integer, ByVal UpStrokeVelocity As Double, ByRef LoadTime As Double, ByRef LoadCurrent As Double, ByRef UnloadTime As Double, ByRef UnloadCurrent As Double) As Integer

  ' Search for electronics

  RC = bfx_autodetect_SearchPiezo (False, PiezoElectronicsPort, PiezoElectronicsDev)

  If rc = 0 then MsgBox("No electronics could be detected", MsgBoxStyle.Critical)"error message LogLabel.Text ="no electronics could be detected.

  On the other

  Action.Enabled = True '

  Device found-> activate the button LogLabel.Text = "Piezoelectronics" found on the Port & PiezoElectronicsPort

  RC = bfx_piezo_OpenPort (PiezoElectronicsDev) ' establish communication

  If rc = 0 Then LogLabel.Text = "open e".

  End If

  End Sub

  Private Sub Action_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Action.Click

  Dim rc As Integer ' to store the return code of the dll

  Dim LoadTime, LoadCurrent, UnloadTime, UnloadCurrent As Double ' to store the values returned by the dll

  RC = bfx_piezo_ConfigurePiezo (PiezoCapacity, PiezoVoltagePerStroke) ' Tell the dll of the distributor of physics

  If rc = 0 Then LogLabel.Text = "Configured distributor" "configure the parameters of dosage

  RC = bfx_piezo_SetupPiezo (stroke, beat down, HoldTime, ascending, UnloadTime, UnloadCurrent, LoadCurrent and LoadTime) rc += bfx_piezo_Repeat (repetitions, RepeatDelay)

  If rc = 0 Then LogLabel.Text = "Setup dosage settings."

  Only four interested features me search piezo, open port, configure piezo and piezo installation, as seen on my block diagram. My questions concern only the setup functions / openport piezo and how I built the library call nodes function, since these would also address how to set up the other two. When running VI, I get the error code is 1517, with installation function highlighted, leading me to believe that I have this feature badly adjusted upward (and Potentially openport, explained in the next paragraph).

  Function to open the port has two string parameters that are passed by reference, and configure the function takes one of the following strings as a call by value. Can I just wire them together as I did, or is it necessary to do something in the sense of adding a sub - VI GetValueAtPointer to dereference firstly, the pointer to the string and then spend the actual string on the second node?

  To specify the data types in the function library call nodes, I have all channels like C strings, double as double, return numeric values as integers signed 32 (each function returns a digital long I think that for debugging purposes), Boolean as an integer 16 bit signed (after that I forced my Boolean constant in an integer) and one of my numbers in Setup as an integer no signed, as I was told in an e-mail from the manufacturer of the instrument. Should we indicate the call launched by numbers as constants value, or not, since they are not explicitly defined as constants in the code provided? Since they have been specified not as long, I am right to assume signed 16-bit integer for the passage by the digits of the value? Is the Boolean value a 8-bit or 16-bit and signed? If the function has a numeric parameter as a value call, I guess by the wiring in a digital constant, that this value is transferred to the function?

  Again, I apoligize if these questions are too simplistic (and many of them), due to my limited experience programming and possibly scarce documentation of the company during the inspection. I look forward comments about the VI as well, if I had nothing at all just illegal/bad practice.

  Thank you for your time!

  First of all, I'm really not familiar with C/C++ dll, but I remember something the DLL must contain the standard C functions to properly accessible from LabVIEW. I don't know if this is the case here, but lets see more will enlighten this part.

  Second, whenever I have the chance to directly use the simple series commands, I go like this, and I create my own live LabVIEW. As I see in the attached pdf doc, it is possible to order the material through the series without using the DLL (on page 18). If these features meet your needs, I would really screw via VISA program, your life will be much easier...

  Edit: http://www.ni.com/tutorial/3702/en/

• How to call external functions without one. DLL (just using a.) H and. LIB file)?

  Hi all

  in fact, I am facing difficulties on how to get an external function is called in CVI (Version 2009).

  I was delivered with a. H file and a. LIB file to call an external function of my project CVI. The. H file looks like this:

  void exportedFunction(double *parameter);
  

  As far as I know, the external function was written with MS Visual C++ 6.

  So, I tried to link statically to the al extern like this function:

  -Add the. H file and the. LIB file to the CVI project

  -#include the. Folder H when I needed to call the external function

  -do the external function call

  During construction I get unresolved CVI external function call error, so this seems not work.

  I did some research autour and stood up with two possible problems. Maybe one of you can help me get a bit further and do work things out.

  (1) of the code of the 'real' function inside the DLL file that was not delivered to me. Or y at - it a way to get concrete results (calling external functions) with just one. H and a. LIB file (with none. Included DLL file)?

  (2) the external function does not export according to the rules of Style 'C '. The signature of the function in the. H file shows some things don't like

  extern "C" __declspec(dllexport) void __stdcall ...
  

  Or maybe it's a combination of these two issues (missing. DLL + bad export style function)?

  I guess I could get around the incorrect service export style when I managed to write a wrapper around the original function that actually uses Style C exporters. But I guess I need to the. DLL file for this test as well.

  Thank you very much for your answers.

  Best regards

  Bernd

  There is no need for the stuff of dllexport. There is also the option of a static library without any DLL.  But the "extern"C"' is essential, because it forces the C++ compiler, which was probably used to compile the library to use the C calling convention.

  If you are unable to ask the library vendor to provide a version that was compiled using C calling convention is the way to write a wrapper with VC ++ 6 around this library that functions using C calling convertion reexports. Something like

  extern 'C' myfunc1 type0 (type1 arg1,...) {

  Back to func1 (arg1,...);

  }

  for each function, you must use.

  BTW. "unresolved symbol" is the error message from the linker, you can expect if you try to bind the C code against a generation of library with the C++ calling convention.

• Cannot call dllinstall function... on IE8 with WinXP webcheck.dll error message

  Hello

  I get the error message after logging in my machine.

  Cannot call dllinstall function in the c:\windows\system32\webcheck.dll file as the dunction does not exist or is not supported.

  I made no changes at all to do this. Using XP SP3 and IE8.

  Concerning

  I fixed that.

  had to go through the process of elimination, disable startup items.

  turned out to be problem Webcam live messenger.

  uninstalled and the problem disappeared.

• Call the function in the UI part without head

  I develop some app with no head.

  When I change the code in the head part and build - launch. But nothing changes in the part without a head.

  I have another solution call the function in the UI part headless. But whatever it is called.

  Please help me solution?

  The part without head of a long walk without head application is still running in the background. It will not update until you stop the part without a head.

  To stop the game without leading the race, you have three choices:
  (1) build increment in the bar file version - descriptor.xml. This will force the part without head to stop and restart with the new code.

  (2) use the monitor of the device to manually stop your application from running. Then, new launch and your game without head will run the new code.

  3) to implement your own way without a head, like a button that would send a personalized call to headless with (say) action "com.myDomain.myAppName.SHUTDOWN" and when headless receive this invocation, operate you this line:
  BB::application::instance()-> quit()
  This will make the part without head stop, then you run and your part without head will take place the new code.

  I prefer the #3 method, but if you do, don't forget to hide this feature before releasing to the public.

• How to call a function in class library?

  Hi all

  Anyone know how to call a function in a library project?

  I have to call using a resource file in a library of a CLDC project project.

  So I write a simple test library and tried to access a function in my CLDC application.

  I tested with 2 following projects.

  1. a library project: TivitFirm

  Sorry I can't answer this from the point of view of the eclipse, I use JDE.  But I suspect that the approaches are similar, even if the detail is different, so maybe this will help you.

  In JDE, you have two options:

  (a) use a jar

  (b) create a dependent project

  (a) I usually use a jar.  So to do this I have a workspace is the library, I compile this, then in my project that uses it, I add the jar to build settings

  (b) in this case, you have two projects in the space of a job, and you say the main project that it is dependent on the library project.

  I hope this helps.

• How to call the function cascade BlackBerry

  I begineer in blackberry c ++.

  I do two class is testobject and second in test .i call the onther text function average () and nexttext();

  so please how to call this function.

  // Default empty project template
  #include "TestObect.hpp"
  
  #include 
  #include 
  #include 
  
  using namespace bb::cascades;
  
  TestObect::TestObect(bb::cascades::Application *app)
  : QObject(app)
  {
      // create scene document from main.qml asset
      // set parent to created document to ensure it exists for the whole application lifetime
      QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
  
      // create root object for the UI
      AbstractPane *root = qml->createRootObject();
  
      // set created root object as a scene
      app->setScene(root);
  }
  
  void TestObect::test(){
  
      qDebug()<< "****************Naveen";
  }
  

  I insert also declared in the header file.

  Q_INVOKABLE Sub test();

  then I create another test class.

  /*
   * test.cpp
   *
   *  Created on: Apr 2, 2013
   *      Author: nksharma
   */
  
  #include "test.h"
  
  test::test() {
      // TODO Auto-generated constructor stub
  
  }
  
  void test:: nexttest(){
      qDebug()<<"***********Next test*********"
  
  }
  test::~test() {
      // TODO Auto-generated destructor stub
  }
  

  error in the file namespace,

  here in file herder

  the namespace error

  /*
   * test.h
   *
   *  Created on: Apr 2, 2013
   *      Author: nksharma
   */
  
  #ifndef TEST_H_
  #define TEST_H_
  
  class test {
  public:
      test();
      virtual ~test();
       Q_INVOKABLE void nexttest();
  };
  
  #endif /* TEST_H_ */
  

  You have a space between the colon and the n in:

  void test:: nexttest()
  

  Another thiing, if you are using Q_INVOKABLE, you must declare Q_OBJECT in your front header file public:

   

  
  If you're still having problems, try to clean up the project with Project > clean...