require external dll function prototypes

Similar Questions

• VI = external dll function pointer reference?

  So I'm porting this simple program in C in LabVIEW. It receives signals of a haptic (Sensable Phantom Omni) material. It should be simple, but it showed several complications. (been stuck for 2 weeks )

  I managed to import the material with all its functions DLL (using LV 8.2, because 8.5 and 8.6 Assistant sucks).

  But there is a function whose argument is a function pointer:

  hUpdateHandle = hdScheduleAsynchronous (updateDeviceCallback, 0, HD_MAX_SCHEDULER_PRIORITY);

  I already have the corresponding VI to updateDeviceCallback (which is a (void *) who don't really use and returns an int).

  hdScheduleAsynchronous is part of the API of the material (I'm not kidding with her, and I know what's inside), and as first argument expects a function pointer.

  Can I use the node reference to open VI to get the "pointer" for my VI and then feed him as an argument for the external DLL? How to properly mount the ref VI data type in a function pointer?

  Although DLL probably uses the C calling convention and then Visual C like prefixing underscore before the exported name. Node to call library of LabVIEW bypasses that you entered because when he's trying to GetProcAdress a function name, and the operation fails, it automatically retries with the name of function with added underscore. For your own "Wrapper"DLL", you will have to do something similar, or use the right name.

  But while the reminder THAT DLL is indeed must be written in C to avoid trouble, functions to load the library and GetProcAddress can be easily implemented directly in LabVIEW by using the node library call. It lets more easily play you with such things as the function names.

  Rolf Kalbermatter

• TestStand can not find that all exported DLL functions

  Hi all

  My problem is the following:

  I have a DLL that I compile with Visual Studio with 40 functions. When I want to use this DLL in teststand, there are two missing functions. If I check with the dependency walker, the 2 missing function in teststand tool are well implemented.

  The missing function prototype:

  struct HModemBoardOpaqueType * mbCreateModemBoard (void)

  Good function prototype:

  enum UbtDllErrorCode mbDisconnectFromModemboard(struct HModemBoardOpaqueType *)

  Is that possible that teststand does not structure opaque type correctly?

  If I export my function type C (with extern C) no function is missing from the test bench

  Thank you

  What version of TestStand do you use? Older versions of TestStand only supported zero, digital and Boolean data types for the return values of the adapter of the dll. More recent versions of TestStand are now supported pointer/handle as well. New versions of TestStand I expect you can use such a prototype with the handle/pointer data type. However, if you want to convert this struct to an equivalent TestStand custom data type, you need to make a parameter instead of a return value, as the card does not support the conversion of struct for return values.

  Basically returning a struct pointer this way (as return value) is dangerous in C/C++, because it is not possible to know who owns the memory. The type of pointer/handle allows you to do anyway, but it must be properly to maintain life of memory return you at a lower level (i.e. maybe with an exported function that uses the pointer who knows how free it).

  Hope this helps,

  -Doug

• External DLL with struct array

  I am train (new to this) call an external dll.  The function prototype looks like this:

  int FUNCTION (int * count, struct List_t * list);

  Count is of type Long

  List_t is a structure that looks like:

  typedef struct List_t
  {
  char name [MAXCHARS];
  char file [MAXCHARS];
  double length;
  bool wired;
  bool DDD;
  };

  and the list is an array of length (MAX-1), where MAX is defined as 10 and MAXCHARS is 48.

  This is my last try:

  

  and I have the List parameter as "adapt to the type" and "pointer of table data.

  I get correct data, but not all.

  Thank you

  And increasingly what said tbob, you better make sure the entrance of County is never greater than 1, as the function could otherwise try to fill only element that you pass and what can AND will damage your memory eventually causing some breaks down, but has no need to plant immediately beyond the end of the table.

  What you should probably do is to replace the node Build array by Array Node initialization and son County control also at the entrance to the size of it. Set the number at 10 and use the number of output to resize the table using table to reshape the size that was filled in.

• Why the DLL function performed by call library node fails when the Vi is reopened?

  Development system

  OS: Windows XP

  LabVIEW: version 10.0

  DLL: Custom

  Compiler: Visual C++ 6.0

  Function prototype: __declspec (dllexport) const char * test (void)

  We have developed a DLL to use.  Compile the DLL itself.  The DLL includes a function test.  The test function validates the functional capabilities of the DLL.  I followed the examples online, and I used the tool to import shared library in LabVIEW.  The screw created use the call library node.

  When I create a VI by calling the function in the DLL test customized by using the call library node the VI runs the test DLL function flawlessly.  I close the VI.  When I re - open the VI and run it, I get an error code of the DLL.  However, if I go on the schema and define the path of the DLL in the library call Configuration node once again the VI then runs the test DLL function perfectly again.

  I have set the path of the DLL in the library call Configuration node everytime I open the VI.  The examples that I downloaded from the community don't require this.  What could be the missing DLL?  What Miss me?

  I solved the problem.

  I had create the DLL by using the following steps for VC 6.0:

  1. new project

  2. Select the Appwizard (DLL) MFC

  3. Select the regular DLLS using the MFC shared DLLS

  4 Yes for source file comments

  5 finishing

  The DLL must be on the VI search path.  The easiest way was to have the DLL in the same directory as the VI.

• Problem with the help of DLL functions

  Hello.

  I'm writing a DLL that calls the functions of a DLL camera and them ends and passes of LabView. I wrote some code of practice and the dll of passage of functions and events with Labview and LabWindows/CVI DLLs, so I like to think I have a reasonable understanding on what I'm trying to do. However I keep getting errors in calling the functions of DLL functions camera I want to use in my DLL.

  I have two functions in the camera DLL, XC_AddImageFilter, and XC_RemImageFilter, I would like to wrap and put at disposal in my DLL. When I compile I get the following errors:

  2 link project errors, Undefined symbol '_XC_AddImageFilter' referenced in "ImageFilter.c". Undefined symbol '_XC_RemImageFilter' referenced in "ImageFilter.c".

  I tried to tweak the prototypes in my header file and the change in functions but nothing I try seems to work. I connected the camera DLL in my project in a way that was previously successful with another practice DLLs and I browsed this forum for similar problems, but I can't seem to find a soloution.

  Thank you for taking the time to read this. I hope that you will be able to help me with my problem.

  PS I had problems to join my code so I put an extension .txt at the end and apparently has worked so please forgive the suspicious file extensions.

  Sorry!

  I do not understand the Labview.lib file which is why Labview functions weren't working! Duh!

  #begginer errors!

• dll function does not

  Hi all
  I try to use the dll function and one of them always returns 1 (error), and I don't know if I'm doing womething wrong.

  the datasheet of the dll wrote:

  Prototype: int WINAPI rf_M1_authentication2 (unsigned short icdev

  unsigned char model,

  unsigned char block,

  unsigned char * pKey)

  Parameter: icdev: [IN] device ID

  model: [IN] button validate mode

  block: [IN] absolute block address

  pKey: [IN]

  password of 6 bytes

  Return: returns 0 in case of success

  Explanation: model = 0 x 60: via KeyA

  model = 0x61: via KeyB

  The prototype of my function is:

  int32_t rf_M1_authentication2 (uint8_t icdev, uint8_t model, block uint8_t, uint8_t * pKey);

  Any idea?

  Thank you

  Hello

  I finally found the solution using Labview calls to place my table in an area of memory and pass the pointer to my dll. Here is the code:

  

  Thank you all!

• Qosmio G10: Scanner uninstall problems - cannot load the external DLL

  I tried to uninstall an old scanner HP my Qosmio G10 and received the message - internal error unable to load or call external DLL, please contact you provider for more information. If I could use the product to restore disc and all saved this would restore the system to the way I bought it or are ther programs on the CD-ROM tools & utilities.

  I am a novice at this so any help is appreciated. Thank you emdpar

  HI Michael,

  You can certainly use the recovery of the product CD to re - install your system to its original state, but this seems a little extreme just to remove an old hardware device to your configuration. You should not need to use the tools and utilities disk unless it contains items that are not in the recovered system.

  I assume the error with the uninstall wizard is because only the original installation used a product CD that cam with scanner HP and the missing DLL is on this CD.

  Kind regards

• Modified dll function does not not right

  I have a bunch of the DLL created a c# project. So far I managed to use DLL functions in Labview with the nodes in the palette of .NET.

  My problem is this, I made a few minor changes to the behavior of a function in the DLL in Visual Studio, but when I try to run this same feature in Labview, it still has the old behavior, as I've not updated at all. (I even started a new VI just to implement the nodes and the.) DLL file contains the date of last modification as a few minutes before, does still not work well)

  Does anyone know why this might be happening?

  Go to View > .NET assemblies in memory to verify the location of the DLL.

• Two parallel executions, calling a DLL function

  Hello

  Since this test takes about 6 hours to test my USE, I plan to use the parallel model to test 2 UUT at the same time in parallel.

  I implement the test code as a DLL of CVI.

  However, to my surprise, it seems that the steps that call a DLL function actually traveled in one series, not in parallel:

  Test 2 power outlets if one enters and executes a DLL works, the other waits for the first to complete its operation and return. While the other runs on the same copy of the DLL, so that the DLL global variables are actually shared between executions.

  So if a DLL will take 5 minutes to complete, two executions in the running at the same time take 10 minutes. This isn't a running in parallel in every way.

  What I want and expect also TestStand, was to completely isolate the copies of these two executions DLL such as test two casings could run at the same time the same DLL function by arbitrary executiong their copy of the function, completely isolated from one another.

  So they separated globals, discussions, etc., and two parallel jacks take 5 minutes to run a step, instead of 10.

  Such a scenario is possible?

  If not, how can I use my test in parallel (in truly parallel) when the use of 2-socket test?

  (1) Yes, he'll call the multiple executions in TestStand calling into the same dll in memory the same copy of this DLL. Thus dll called in this way must be thread-safe (that is written in a way that is safe for multiple threads running the code at the same time). This means usually avoiding the use of global variables among other things. Instead, you can store the thread shows in local variables within your sequence and pass it in the dll as a parameter as needed. Keep in mind all the DLLs your dll calls must also be thread-safe or you need to synchronize calls in other DLLs with locks or other synchronization primitives.

  1 (b) even if your dll are not thread-safe, you might still be able to get some benefits from parallel execution using the type of automatic planning step and split your sequence in independent sections, which can be performed in an order any. What it will do is allow you to run Test a socket A and B Test to another socket in parallel, and then once they are then perhaps test B will take place on one and test one run on the other. In this way, as long as each test is independent of the other you can safely run them in parallel at the same time even if it is not possible to run the same test in parallel at the same time (that is, if you can not run test on two Sockets at the same time, you might still be able to get an advantage of parallelism by running the Test B in one take during the tests in the other. See the online help for the type of step in autoscheduling for more details).

  (2) taken executions (and all executions of TestStand really) are threads separated within the same process. Since they are in the same process, the global variables in the dll are essentially shared between them. TestStand Station globals are also shared between them. TestStand Globals file, however, are not shared between runs (each run gets its own copy) unless you enable the setting in the movie file properties dialog box.

  (3) course, using index as a way to distinguish data access are perfectly valid. Just be careful that what each thread does not affect data that other threads have access. For example, if you have a global network with 2 elements, one for each grip test, you can use safely the decision-making of index in the table and in this way are not sharing data between threads even if you use a global variable, but the table should be made from the outset before start running threads , or it must be synchronized in some way, otherwise it is possible to have a thread tries to access the data, while the other thread is created. Basically, you need to make sure that if you use global data which the creation/deletion, modification and access in a thread does not affect the global data that the other thread use anyway in or we must protect these creation/deletion, modification and access to global data with locks, mutex or critical sections.

  Hope this helps,

  -Doug

• List of dll functions

  Hi, I tried to get the current list of all dll functions. Here is my code: tsErrChkMsgPopup (TS_StepGetModule (StepHandle, & errorInfo & cviModule)); error = TS_CVIModuleAsCommonCModule (cviModule, & errorInfo, & commonCModule); sprintf ("c:\\Temp\\%s", sztemp, szdll); error = TS_CommonCModuleSetModulePath (commonCModule, & errorInfo, sztemp); error = TS_CVIModuleSetModuleType (commonCModule, & errorInfo, TSConst_CVIModuleType_DLL); error = TS_EngineGetAdapter (EngineHandle, & errorInfo, County, & commonCAdapter); error = TS_CommonCAdapterGetDllFunctions (commonCAdapter, & errorInfo, sztemp, & dll_func); Problem was found in the last line. Direct connection between commonCModule and commonCAdapter was non-existent, so I ask for EngineHandle of commonCAdapter, because GetDllFunctions is only for commonCAdapter. Can you help me with this? Best regards, branar

  You don't need a module for a list of the functions of the DLL. Here's some pseudocode for what you need to do:

  Adapter CommonCAdapter = Engine.GetAdapterByKeyName (AdapterKeyNames.FlexCVIAdapterKeyName);

  DllFunctions functions = adapter. GetDllFunctions (path);

  for (int i = 0; i)< functions.count;="">

  {

  Function DllFunction = functions [i];

  String nomfonction = function. DisplayName;

  Do something with functionName.

  }

• How to show the function prototype

  Hello

  If I type a function in the editor of CVI, a popup appears with the function prototype, as I type ("support". This is very useful, but it only works if I type the complete function. If I jump on another line, then back to the function, it doesn´t show the prototype more. To do this, I have to go to the support, delete, then type the new. Then reappears this aid.

  Is there a quick way, for example the shortcut, which displays this help, or I have to type the support every time, when I need the prototype?

  concerning

  mitulatbati

  I think you're looking for this shortcut: ctrl + shift + space.

  Kind regards.

• DLL function called change of entry

  Hello world

  I know that it is very basic; but I am not by my own. I am very new to LabVIEW and was not able to find a solution in the forum.

  I want to call a function in a DLL, every time when I press a button; but unfortunately, the function is called only when starting.

  So, how can I call a DLL function on a change of some of the entries?

  I have attached a screenshot. I tried the stuff. It did not work. Now, the function is called twice during startup.

  Thanks in advance and best regards,

  Chris

  If you want to call anything with a button, use a structure of the event with a value change event.

  I would recommend that you take one of the free LabVIEW tutorials available on the site and see examples of delivery - help > find examples.

• External function with a pointer to a callback within a DLL function

  Hello.

  I am loading a DLL and try to call a function with the following prototype:

  Func1(HANDLE, hHandle, LPVOID (*pCallback)(UINT, UINT LPVOID), CHAR* sPath)
  

  Now, I have no problem with the types of variables, because CVI 9.0.1 recognizes each of them and I have no problem with LoadLibrary() and GetProcAddress().

  But, how to pass a pointer to a callback function that is inside the DLL, I am trying to use.

  I tried to declare the callback like this:

  LPVOID (CALLBACK Callback)(UINT iDevNo, UINT evEvent, LPVOID pData);
  

  and call the Func1 function like this:

  (Func1)(hHandle, &Callback, NULL);
  

  but it irritates me:

  Symbol not defined "_Callback@12" referenced in "source.c.

  Hopefully I can help.

  I appreciate your time on this issue.

  Kind regards.

  Hi Daniel,.

  He must first make sure that the callback function is exported by the DLL, so the program that uses the DLL can access the identifier of the function name. Then you must make sure that you call GetProcAddress not only on Func1, but also on the exported callback function. You must store the two address function values in their respective function pointers. You can then pass the pointer to callback in the form of argument to the call to Func1.

  It's probably cleaner if you set of typedefs for all your function pointers, in the calling program:

  typedef LPVOID (__stdcall * CallbackType) (UINT, UINT, LPVOID);
  typedef? (__stdcall * Func1Type) (HANDLE, hHandle CallbackType, CHAR *);

  ...

  CallbackType CallbackPtr;
  Func1Type Func1Ptr;

  ...

  dllHandle = LoadLibrary ("... ») ;
  CallbackPtr = (CallbackType) GetProcAddress (dllHandle, 'Callback');
  Func1Ptr = (Func1Type) GetProcAddress (dllHandle, "Func1");

  ...

  Func1Ptr (..., hHandle, CallbackPtr, NULL);

  Boa kind!

  Luis

• allocation of an array of 2d in labVIEW and move to the DLL function to obtain data

  Hi all!

  I searched a lot about this, but one cannot find any solution. Please find attached the vi that I try to get a unit of 32 channels data,

  100000 samples per channel with 14-bit resolution. And please also find enclosed the header for my dll file. (in the header, it is the GetBuffers function).

  There is not a lot of data, it is a little more then 6 MB in the task of LAbVIEW Manager eats about 30 MB more memory, then it should. Are there explanations why?

  Because there is much more data in a single channel (million samples or more)

  Then I will try to allocate a 2D to data array, but when I try to run my LabVIEW vi crashes.

  Could you please help?

  Best regards

  Tomzi

  Dear Tomzi!

  To allocate the data in a table in LabVIEW, you must always initialize, as in a you must have a valid entry on cell (x-, y - 1) have a size of table of (x, y). It is usually best to use the function Array initialized for this purpose.

  There are ways to pass arrays 2D to DLLs, cand find you examples of both in examples > communicate with external Applications > external Code using the > integrating DLLs > DLL.vi call. Basically, LabVIEW can pass in the form of a big table 1 d 2D tables, so you'll need to spend too much table size index it. If you pass the array 2D handles it is preferable to use the typedef that LabVIEW generates for you, something along the lines of

  / * LabVIEW created typedef * /.
  
  typedef struct {}
  
  	Int32 dimSizes [2];
  
  	Double elt [1];
  
  	} TD1;
  
  typedef TD1 * TD1Hdl;

  I hope this helps.

  Best regards:

  Andrew Valko

  NOR Hungary