First, I'd like to clarify that the manufacturer provided example code in Python, which works fine. 

I've tried this both using the wizard, and Call Library Function Nodes. I must say, I don't really understand the wizard at all, as it seems to make no attempt to actually parse the provided .h file (it complains about missing preprocessor definitions, which as far as I can tell are already in the .h file, and it complains about e.g. windows.h not being found, even when I explicitly add its complete path to the "Include Paths" section).

Tbh I'm not remotely sure what, if anything, I need to add to includes and preprocessor definitions. 

Using the Function Node, LabVIEW immediately crashes, despite my attempt to follow the examples (see my .vi).

Here's the key call which works in Python:

pcproxlib.usbConnect.restype = ctypes.c_short
rc = pcproxlib.usbConnect()
if rc == 1:
	rawData = ""
    buffer_size = ctypes.c_short(32)
    pcproxlib.GetActiveID32.restype = ctypes.c_short
    # create a buffer of given size to pass it
    # to get the raw data.
    raw_data_tmp = (ctypes.c_ubyte * buffer_size.value)()
    #as per documentation 250 millisecond sleep is required
    # to get the raw data.
    time.sleep(250/1000.0)
    nbBits = pcproxlib.GetActiveID32(raw_data_tmp , buffer_size)
pcproxlib.USBDisconnect.restype = ctypes.c_short
pcproxlib.USBDisconnect()

I've attached the .h file, and the .vi file of my failed attempt at using the Function Node. 

How on earth is one supposed to figure all this out de novo?

pcProxAPI.h pcProxAPI test.vi

I used Wireshark to capture the coms between the PC and the camera unit while sending the Pan  Tilt and Zoom calls from a customer provided software. I also have SDK file from camera folks.

I have limited experience in creating CIN nodes from DLL. I was hoping that instead of creating CIN nodes to control PTZ functions, i can do the same over TCP/UDP interface. I was also wondering if *.pcapng captured using Wireshark has that information.

Can some one review the info and let me know if it's possible? I can provide SDK if some interested.

Description of DLL AJNetSDK.pdf PTZ Cam data.pcapng

#include<stdlib.h>
#include<stdio.h>
#include<stdint.h>
__declspec(dllexport) int* get_results(){

int *array;
array=malloc(3*3*sizeof(int8_t));
int a=0;
for (int y=0;y<3;y++){
    for(int x=0;x<3;x++){
        int index=y*3+x;
        array[index]=a;
        a++;
    }
}

return array;

}

for this I get "get results.vi" which after running it I only get a negative number.
and for this one :

__declspec(dllexport) int get_results(){

int *array;
array=malloc(3*3*sizeof(int8_t));
int a=0;
for (int y=0;y<3;y++){
    for(int x=0;x<3;x++){
        int index=y*3+x;
        array[index]=a;
        a++;
    }
}

return *array;

}

I got get results1.vi which I get nothing after running the vi.
I don't know how should I make the function or dll that I get the array from the vi that shared library wizard gives me
please help me

get results1.vi get results.vi

background

A while ago I wrote a dll wrapper to get data from dedicated test-hardware. For this hardware there is a dll available.  To use this dll you need to use an callback function. If you need to use a dll in Labview which needs a callback you need to write the callback in C code and use a Labview C lib to get the data into Labview, basically my dll takes care of this problem .

Enhance the code and way of working more efficient

The code I wrote code works fine. However I did not use / test it for hours on a row. And sometimes If I make a mistake when changing the code I run into problems. I was able to fix all the errors and problems however it was not the most efficient way of working. For instance If there  is a serious error in the code the dll I need for the hardware can crash, it can make my wrapper crash, which will in return make Labview crash. This makes the way of coding inefficiënt and it will not enable me to read my C++ book etc etc.

Example pseudo code

I did try to extract some main points of intrest from the code, I did add some comment in the code. I hope someone can give me some general guideline or advice what to read.

At this time I am reading:

Unhandled C++ exceptions

I think I might be able to use it, I did not use this before so advice would be welcome.

Thank you all for the help !

// ..
// This is a part of the code only intended to have a talk about how to catch errors 
// It is not complete and intended as Pseudo code
// ..


int __stdcall MyDriverLoads(const int NumberToInitialise,const bool enableAnotherOption , const char *const path , LVUserEventRef *rwer)
    {
		
	// loads the dll 
	// Q -- I can check if (F_functionname !=0), if it is not 0 then I can proceed if the function returns 0 I can return an error to Labview
	Extern_dll =	Load_Extern_dll();
		
	// Get the functions I need from the dll
	p2_ExternDriver F_ExternDriver = 	(p2_ExternDriver)GetProcAddress(Extern_dll, "_ExternDriver");
	
	p2_Initialise F_Initialise = 		(p2_Initialise)GetProcAddress(Extern_dll, "_Initialise");	
	p2_AdapterCount F_AdapterCount = 	(p2_AdapterCount)GetProcAddress(Extern_dll, "_AdapterCount");	
	p2_StartLogging F_StartLogging = 	(p2_StartLogging)GetProcAddress(Extern_dll, "_StartLogging");	

	p2_StopLogging F_StopLogging = 		(p2_StopLogging)GetProcAddress(Extern_dll, "_StopLogging");	
	
	
	// When there are adapters found I tell it in Labview
	adapterCount = F_AdapterCount();
	
	
	// Get the callback function adress, if adress == 0 I can see something is wrong
	void(__stdcall *p2_CallbackFunction_t) (pt2Obj , const LogData & ) = &CallbackFunction;
	
	
	// Q -- I could use try {} and catch {} however I do not have acces to the source code of the dll so,
	//		I do not know if they used 
	//			trow "The Blue error" , or
	//			trow "The Red error"
	
	ret = F_ExternDriver(adapterCount, enableLogFile, path, *p2_CallbackFunction_t, pt2Obj);
	
	// This tels the dll to start logging before this command you will not receive data in Labview
	ret F_StartLogging(1,2,3);
	
	// Labview is receiving data thats great !!!
	
	return ret;
	// Q -- Labview has been receiving data for a hour what happens if the used extern dll crashes ??
	//		If the dll crashes when return is passed I can not use try() and catch anymore.
	// 
		
	}
	
	


	extern void __stdcall CallbackFunction(pt2Obj , const LogData & )
		{
		// There is a lot to do here 
		// do stuff!!
		// I did not write everything here
		
		err = PostLVUserEvent(*event_ref, &tmpEvent);
	
		}

What I want to do

I got a dll with a wrapper, this dll and wrapper can be used for a special datalogger. The wrapper contains multiple functions, I have got some of them working using a CLFN, for instance I can read a jumper setting from the datalogger in LabView. So far everything is fine.

Of course I am not that interested in the jumper setting, I would rather use the datalogger to log data.

I need to run one function to start logging. When there is enough data in the databuffer of the driver dll it will call a callback function I need to write in Labview, here is the function which starts the logging as described in the header file:

Int LOGEXPORT __sdcall LOG_StartLogging{const char ** logFilename, ptLogCallbackfunction ptFunction, ptObject ptObject}

logFilename needs to be a NULL pointer, from my understanding I do not need to do anything with it. Only provide it. If I do not do anything with it some data is saved at a default location.

ptLogCallbackfunction, as far as I know I need to provide a pointer to the callback function

ptObject ptObject, this must be a void pointer

The header also provided how the callback function could look like in 😄

Void __stdcall callbackLog(ptObject object, const int ArraySize, const StructLogdata *const logDataArray)

{

// copy data from logDataArray for use in my code

}

StructLogdata is a struct with different datatypes.

What I did try

I did a search on internet there are some examples about callback functions, most of them point to NET and active X. They use a reg Event Callback. I did read the helpfile at the end of the helpfile there is the text:

“Use the Event structure or the Register For Events function to register and handle non-.NET or non-ActiveX events dynamically” I am having a hard time to find a proper example. I did find this site with some information:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P8XJSA0&l=nl-NL

and this one about the refnum:

https://forums.ni.com/t5/LabVIEW/Passing-Event-Refnum-to-Call-Library-Function/td-p/4107748

So I did make a user event, I wired a static Vi ref containing a callback vi to the input of this user event. I did wire the user event to a Reg event and wired the event registration refnum to the start logging dll call library function node function pointer input and also to an event structure. I did place a counter in the event structure. But nothing happens besides for an exception which makes Labview crash.

The parameters I did use in the call library function are:

logFilename: type numeric, datatype: Signed Pointer-sized int Pass: pointer to value

ptLogCallbackfunction: type: adapt to type, Data format handles by value (tried all options)

ptObject: same as logFilename

I did try a lot of different things. Writing them in this post will result in chaos and I don’t want that. I hope someone can help me with a simple example how to make this work, or point me into the correct direction.

Thank you all for the help!

Sending a cluster with int's

I did manage to send an array with clusters from a dll to Labview. Thank you all for the help. You can find the link here:

https://lavag.org/topic/22877-can-someone-help-me-with-an-example-for-an-existing-wrapper-dll-which-uses-function-pointer-with-callback-function/#comment-147496

It works fine I am very pleased with it. 😃

Sending a text string 

I did got a example here: 

https://forums.ni.com/t5/Example-Code/Posting-Events-to-a-LabVIEW-Event-Structure-From-a-Dll/ta-p/3996283

Tested it and it works fine. Again I am happy 😃

Sending a cluster with int's AND a string

Now I want to send a cluster / struct with a couple of int's AND a string of text. I Got a example of how to send text from a C / C++ wrapper to Labview, can someone please help me out? The thing I do not get is, how to combine the both examples. Is "sizeof(structSample)" valid with a LStrHandle in it? How do I copy the data from the string to the struct, etc. Can someone change the code example or help me with the example so it works? I did add some text to the example code to make it more clear I added +++ signs in my comment in the code.

Hope someone can help me. Thanx !

// LVUserEvent.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"
#include <stdio.h>
#include "LVUserEvent.h"

#define STRING_LENGHT 256				//Can be any size

// ++++ I want to send this Cluster/Struct to Labview
typedef struct {
		int firstInt;
		int secondInt;
		int thirdInt
// +++++ I try to add this, Gues this will not work .. see extcode.h 		
        LStrHandle textString[TEXT_STRING_SIZE];        
		}structSample;										

typedef struct{
        int32_t size;
        structSample elm[1];
   }totalstructSample, **structHdl




LVUSEREVENT_API void SendEvent(LVUserEventRef *rwer)
{
	LStrHandle newStringHandle;

	//Allocate memory for a LabVIEW string handle using LabVIEW's
	//memory manager functions.
	newStringHandle=(LStrHandle)DSNewHandle(sizeof(int32)+STRING_LENGHT*sizeof(uChar));
	
	// +++++ OW no another one ... 
	structHdl = (eventHdl)DSNewHandle(sizeof(totalstructSample));
	
	
	
	Sleep(2000);
	PopulateStringHandle(newStringHandle,"+++ Dear int I don't want you in my PostLVUserEvent");
	
	//Post event to Event structure. Refer to "Using External Code
	//with LabVIEW manual for information about this function.
	PostLVUserEvent(*rwer,(void *)&newStringHandle);



	return;
}

void PopulateStringHandle(LStrHandle lvStringHandle,char* stringData)
{
	//Empties the buffer
	memset(LStrBuf(*lvStringHandle),'\0',STRING_LENGHT);
	
	//Fills the string buffer with stringData
	sprintf((char*)LStrBuf(*lvStringHandle),"%s",stringData);
	
	//Informs the LabVIEW string handle about the size of the size
	LStrLen(*lvStringHandle)=strlen(stringData);
	
	return;
}

I have several apps that rely heavily on Excel 2016 , I cant use the report generation stuff since some of the machines do not have LabVIEW (2019) Pro only base or full.

unfortunatly I cant rely on IT to warn me when they are going to switch ... 

TIA

Dan

I am trying to implement a Python script in LabVIEW to convert FITS file into visible image (JPG,PNG).

My progress so far:

1. I am able to call a simple Python script and it runs perfectly (AddTwoDoubles).

2. I am able to download and display an image on Jupyter (see screenshot Result on Jupyter.png)

3. I downloaded Jupyter notebook file as Python file (FITS to JPG converter.py), trying to call it in LabVIEW (see snippet Call_python_script.png).

My issues:

1. When I call the Python script without indicating a Function, LabVIEW gave me an error (error out.png) saying Function could not be found in the module. I wonder if I can just call the script without calling any function and the script can be executed thoroughly?

2. In case the script can be executed, how do I display plotted image in LabVIEW?

Does anybody have experience or idea on this issue?

Thank you for your time checking my post!

FITS to JPG converter.zip

Look at the code :

Not being able to read directly with LabVIEW I tried in C to read this same file by using the same functions, I obtain well the expected string.

What confirms me in my idea that the problem comes from LabVIEW or my parameterization of the call of the DLL.

Can you help to understand my problem ?

I put you in attachment a file composed of the VI on which you have the code trying to read the DLL, the dll hdf5 and a capture of the code in C.

NB :
I use LabVIEW 2020 64 bits.

DLL_HDF5.zip

# Problem
The DLL FTMProLib has a function called GetSpectrumData. This function requires an int of spectrumtype and a pointer to pSpectrum). (see attachment Page_FTMProLib_GetSpectrumData.jpg)
This pSpectrum is of the type Spectrum, which is a struct. (see attachment Page_FTMProLib_Spectrum.jpg)

In the Spectrum struct there is a double called pdSpectrum which contains my spectrum data. However, different from the other elements, this is a pointer.

I know how to call a pointer to an double array through the DLL in LabVIEW. However, this pointer is nested inside the pointer to the Spectrum struct.

When generating the DLL, LabVIEW created the control shown as "pSpectrum oud"  in 2022-10-05_Labview_library_control.png.
As one can see, the pdSpectrum is not an array, but a single number field.
I tried to change this to an array, as shown in "sRawData". However, when I use this new control format, LabVIEW crashes (see 2022-10-05_Labview_library_error.png).

The Labview program is working when using the pSpectrum oud control, which to me suggests that I need to add a pointer to the double array in this single number field.
But I've no idea how to do this, since labview is not working with pointers.


So far I've no luck into getting this working and I'm out of ideas how to approach / fix it.

Any help appreciated.

Create a file called test.m which just has:

a=a+1;

Next create a vi that has a Matlab Script Node with inputs and and outputs of "a" attached to a control and indicator respectively which only contains a script node with the code:

cd <whatever directory test.m was saved to>;

test

If you run this code with the control set to 0, the indicator will read 1 as expected.

Now, if you go edit the file test.m to a=a+2; (without closing your vi) and then rerun the vi, it will still give you 1, not 2. If you close the vi, then reopen it, it will give you 2 as expected.

Is there a way to generate new execution code for LabVIEW without closing the vi and reopening it.

ER_CODE KMAPI CLGetMeasData(DEVICE_HANDLE hDevice, CL_COLORSPACE Type, CL_MEASDATA* pColor); 

typedef union tCL_MEASDATA

{

        CL_EvxyDATA           Evxy;                                       

        CL_EvuvDATA          Evuv;                                       

        CL_EvTduvDATA       EvTduv;                                   

        CL_EvDWPeDATA    EvDWPe;                                 

        CL_XYZDATA            XYZ;                                

        CL_RenderingDATA Rendering;                      

        CL_PWDATA            Pw;                                         

        CL_SPCDATA            Spc;                                 

}

CL_MEASDATA;

I have created one program who call a DotNet assembly component (.NET4   system.dll) and all ok in my LV2011 development ide.

But when I create EXE with it, each time I run the program it calls me .Net ddl path. I do that on the same PC.

If I indicate the path, the program loads it and runs correctly. It's a bit painful and not very professional to do that each time.

To solve this, I have tried lots of work around but without success.

1) Add Dll caller Vi directly in project folder . (intialy in my user folder)

2) Add a specific .ini file where I have added a key for the search path (viSearchPath= "C:\Windows\Microsoft.NET\assembly\GAC_MSIL\System\v4.0_4.0.0.0__b77a5c561934e089") to Help LV to found assembly.

3) Add DLL in my exe construction in data folder

4) etc etc...

I have read and test lots of things on NI website but it's not always clear for me.

If someone can give me a good procedure it will  be christmas  for me.

Eric

I want to create an array of pointers to variants. I seem to be able to write quite happily, but when read; it causes a problem.

The following VI demonstrates what I am trying to do. It runs through once quite happily, but on the second execution it fails on the DSDisposePointer (even though the variant has been written and read correctly). If you disable the read, then it doesn't crash so it must be something to do with the way I'm retrieving the data.

Any help appreciated.

varpointers.vi

The class has several states and will raise an exception when a method is called that is incompatible with the current state.

Are there any best practices for passing exceptions back to LabVIEW? I was thinking of using the LabVIEW error cluster as a return type.

http://www.lvs-tools.co.uk/software/utilities/

But whenever I try to register or login, nothing happens.  (Also, I try to think, but nothing happens.)  Are there any other Labview codes that use the Windows Memory-Mapped Files functions, or should I just reinvent this wheel?  By the way, here is a Microsoft document on the subject: https://msdn.microsoft.com/en-us/library/ms810613.aspx

in my code I'm using "Spline Interpolant.vi" and "Spline Interpolation.vi" (the last one in a for loop) to interpolate an array of 11 elements and the final array has 501 elements. The time required (on my pc) is ~40 microseconds.

I have to do the same operation thousand of times for every measure and, every time, I need to execute also "Splite Interpolant.vi" because the original array will change. I have tried others interpolation method available in LabVIEW but the time required is the ~ same or more; I don't know if there is something else I can try to do to increase the speed of the interpolation. But, at the moment, the time budget between two consecutive measure is very limited.

I have looked at the code of the two vi's and, from my understanding, they are not calling some C/C++ primitive to calculate the 2nd derivative and interpolate; instead it looks like pure LabVIEW till the end.

I found this C++ implementation https://kluge.in-chemnitz.de/opensource/spline/ but it's a "header-only" library and I don't know how to call it from LabVIEW without dll file. Anybody here can help me? can I expect a decrease of the required time? The linked library is just an example, I'm open to any other solutions/library/dll.

Thank you.

Marco.

LabVIEW: (Hex 0x683) The specified Python module could not be imported.
=========================
LabVIEW: (Hex 0x683) The specified Python module could not be imported.

Module Path: C:\STOKE\code\GSW.Deployment.0.1-rc0\yardmaster\yardmaster.py
Function Name: exit
Python returned the following error: <class 'ImportError'>
DLL load failed while importing _ssl: The specified module could not be found.
<traceback object at 0x037E3FA8>

If I run the python script in a Anaconda Prompt command shell it works as expected.  I'm wondering if the Anaconda enviroment has all of the dependancies needed, but not so in the LV session.  

I've tried passing the parameter "function name" as one of the commands listed below with the module parameter as "yardmaster.py" whcih returns an error in LV but works in the cmd  shell (as shown below).

Any ideas and/or help is greatly appreciated. 

SERVO Test Python Node.vi

I need some help. 

Description: it's necessary to launch an app startup.rtexe on a CRIO 9075 (OC VxWorks) then launch a second app app.rtexe from the first one and close first app.

Seems System Ecex.vi might be a great solution, but this function is not available in a palette for RIO which is based on VxWorks.

Maybe anyone could help me or share links with relevant information.

Thanks, Vadim.

The function in the C file:

void getValue(int so, CharacteristicHandle ch, Value *v)
{
    long longValue;
    unsigned long ulongValue;
    double doubleValue;
    char * c_ptr = 0;

    long msgType = g_val;

    sendLong( so, msgType );
    sendCHARhandle( so, ch );

    readLong( so, &longValue );
    v->order = longValue;

    readLong( so, &longValue );
    v->type = longValue;

    readLong( so, &longValue );
    v->label = longValue;

    switch( v->type )
    {
    case integer:
    {
        readLong( so, &longValue );
        v->v.l = longValue;

        break;
    }
    case uLong:
    {
        readLong( so, &ulongValue );
        v->v.ul = ulongValue;

        break;
    }
    case floating:
    {
        readDouble( so, &doubleValue );
        v->v.d = doubleValue;

        break;
    }
    case charString:
    {
        readString( so, &c_ptr );
        v->v.s = c_ptr;

        break;
    }
    }
    return;
}

The definition of "Value" from another header file:

/* Define a type to hold the value and type information for 
 * a characteristic. */
typedef struct Value
{
    union        /* This holds the value. */ 
    {
        long l;
        unsigned long ul;
        double d;
        char *s;      /* If a string user is responsible for 
                       * allocating memory. */
    } v;

    long order;
    valueType type;    /* Int,float, or string */
    valueLabel label;  /* Description of characteristic -- what is it? */
} Value;
 

I'm a newb at CLFN - the primitive datatypes I've got working for my other calls - this one I am not sure how to configure with the CLFN.  Is this possible to do with the CLFN?

I am a Physical Chemist and am just starting Labview (a long way to go, as you may suspect). I would need to do a lot of Daq and DPS but with a low budget (using Arduino and NI-Dev boards for my projects).

I would like to have the option of going hybrid programming (text-G) and since I do not have much programming experience i wanted to know which one would suit my purposes better, C/C++ or python. I have worked with formula nodes, and it is easy for making base computations and mathemathical formula and I was sad by the fact that you either have to use C/C++ syntax or Mathscript as in Math nodes; meaning MatLab inside labview codes.

I am fully willing to put work in if C/C++ is the answer, but I wanted to know which should I pick?

I really appreciate any help you can provide.

Cheers,

Mahbod

def initServer(url):
    server = Server()
    server.set_endpoint(url) 
    ...

The Server object cannot be serialized to JSON as well as cannot be pickled (TypeError: cannot pickle '_thread.RLock' object), so I can hardly see the way how to transfer Server object to LabVIEW.

In that case I managed to store Server as a global variable in python script. This solutions works - I can call functions (ex. start/stop running) that simply use a global Server object.

However, this solution is not secure - because if I lost the python session (due to the LabVIEW issue), I have no access to my Server. That leads to the question:

Is there any more secure way to handle that?

the code goes to the Server_run function and stops here as long as the variable running is true. In C stopHandler will change that and the program can finish.

How we can transfer this functionality to LabVIEW? What should be connected as a second parameter to the CLF node function?

I am trying to find a way to dynamically load and possibly unload .NET DLLs in LabVIEW. This is easy to do when you can use the "Call Library Function Node" to call your DLL by specifying its path on the block diagram. However, it doesn't seem like there is an easy way to do that for .NET DLLs.

I use the .NET constructor node to create an instance of my .NET object which is my DLL, and I use property or invoke nodes to access my DLL methods. 

Does anyone know how this can be done? 

Thank you for your help!

I would like to use the two functions:

int clSerialInit(unsigned long SerialIndex, void** SerialRefPtr);
int clSerialClose(void* SerialRef);

Execute via a Call Library Function Node.

I have chosen the parameterisation shown. But it does not seem to work. The function prototype does not seem to be correct either.

Can someone tell me how to parameterise the call library function Node in order to execute the two functions?

Have a good time, Jim

I assume that means i can interact with Labview Queues in application space, which would be a nice way to transfer information and call back. 

But I cant find any documentation on how to use these eg. documentation or prototypes. If someone can point me in the right direction that would be great!

So I was wondering if people who have been using Python with LabVIEW can give their experiences and describe what set of technologies they use.

I am using LV2018 32bit.

I've been in touch with NI support and so far we haven't come to a solution.

We've tried:

1. Adding a copy of shell32.dll to the build of the exe under always included

2. Modifying the subvi to specify the path to shell32.dll in the CLFN

3. Running as administrator

4. Changing the subvi to use the .NET method found here:  Solved: Invoke Print File (Explorer) - NI Community

5.  Using 'FileMan Print File.vi' in winevent.llb in the attached zip file

They all work on my development PC and on a second laptop, but they all fail and generate an error on this new laptop.

Has anyone seen something like this before and/or have any suggested fixes.

Thanks in advance for any input,

Steve

PrintPDFr1.vi _labview_win_util_32.zip

https://blogs.windows.com/windowsdeveloper/2021/01/21/making-win32-apis-more-accessible-to-more-languages/

maybe you can help me there with an .NET issue.
I try to use the Controller.Open() method from the Citizen.LayoutUtilities.Printing, but it always reports -1 as an error.
There is no LabVIEW error on the constructor or invoke node and the c# example works fine.

This is the Citizen SDK with the manual and examples:
https://www.citizen-systems.co.jp/en/printer/download/sdk-layout/sdk-layout-windriver_V1400E.zip

There are also c# examples included in the SDK which work without problems with the same path/file.

The call as well as the sample code looks not that complicated, not sure what is causing the problem.

I did notice also another strange behaviour with the DLL selection of the constructor.

Adding contructor, choosing DLL the first time:

If I choose the DLL the first time, then the constructor node seems not to to be refering to the DLL.
It's empty and property and invoke nodes do not show anything.

I have to chose then again "Select Constructor..." and select the according DLL again, then I can access invoke and property nodes by the constructor reference without problems.

The second time it works and the node is reffering to the DLL.

I tried it with LabVIEW 2013 as well as with 2020.
Any idea what could be wrong?

bool networkUp = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();

I always seem to fall at the first hurdle with .net, I usually cannot figure out what constructor to use (if any) or in this case even find the method in the GAC or by browsing. As as I understand this method is "global" and does not need any kind of constructor?

Any ideas?

cul --location -H "x-file-format: <FILE>" -H "x-campaign-name: TEST_CAMPAIGN" -H "x-session-name: TEST_SESSION" -H "x-description: DESCRIPTION" -H "x-tags: cc13,test" -H "x-notify-email: user@company.com" --form file=@/data/file.file http://URL

Also this would help on a little script that I am hoping to release at some point. Given the number of curl examples on the internet made a parser that will generate a vi from a curl example. 

• Not be tied to particular versions of Python - LabPython got stuck for me around 2.7.10 and I think was fussy about which compiler have been used. The 2018 native support is restricted to 2.7 or 3.6 I believe (3.7 defintiely doesn't work)
• Not being tied to the same 32/64 bits of LabVIEW
• Being able to offload the Python to a remote server, or go cross platform

I haven't investigated the Enthought package (too much hassle to get a new vendor set up on my University's purchasing system and not really able to justify spending tax payer's money on playing!) which I suspect might be doing something similar.

Anyway, the attached zip file is a proof of concept - it includes a test vi that will try to find an ipython executable and fire it up and you can then interact with it. There's lots of things not properly tested and probably a slew of bugs as well. To run it you need several dependencies:

1. OpenG Toolkit libraries, particularly the LabVIEW Data, string, error and array libraries
2. The JKI JSON library - I had to pick a JSON serialiser and the JKI one seemed as good as any and better than some...
3. The JSONText JSON serialiser library available via VIPM
4. The Zero-MQ Labview bindings - libzmq is the underlying network transport used in Jupyter and there is an excellent LabVIEW bindings library for it.
5. The attached SHA256 implementation so that the communications messages are properly HMAC signed.
6. LabVIEW 2018 - sorry I'm only writing in 2018 now and this code uses malleable vi's with type specialization and asserts in use - so it may not be easy to backport

There's a few things that I'd still like to figure out - primarily the client protocol is very much focussed (reasonably enough) around the idea that the client is sending strings and is interested in string representations of data.I'd like to figure out an efficient way to transfer largish LabVIEW data structures backwards and forwards. I think this probably means developing a custom message handler and registering it with the kernel when the code starts and writing some Python 'flatten to string' and 'unflatten from string' code - but that's only this week's concept....

If you use it, please note that this probably only alpha quality at best -  it may or may not work for you, it may not be safe to use, If it causes any loss or damage or eats your cat then it's not my fault....

Edit 6th March 2019: I've switched the JSON parser to JSONText, found and fixed a few bugs, managed to build a VI package for it that should have the correct dependencies and installs the example client in the LabVIEW example finder.

Edit 19th April 2019: Added more options to connect the example client to remote and already running kernels (and not to shut them down on exit!). Some other fixes as well.

Edit 11th Arpil 2020: Updated the SHA256  version to one that can correctly hash files without reading the whole thing into memory.

university_of_leeds_lib_jupyter_client-1.1.0.6.vip

university_of_leeds_lib_sha256-1.1.2.7.vip

Now when I try to install & run it on a Win10 IoT machine the dll's are not found and throwing errors. Sorry no screenshot at the moment.

The 64bit of PostgreSQL is installed on both machines & works.

The exe of course works just fine on the dev machine.

Does anyone have any ideas? I'm at a loss at the moment & need to get this running.

Thanks.

If I ran my batch file from CMD.exe Windows was replacing the French character with multiple ASCII characters which is obviously not going to work.

The simple solution is to change the active code page to 65001 which is UTF-8. (See: https://stackoverflow.com/questions/11962172/echo-utf-8-characters-in-windows-batch), so all I did was add the

chcp 65001

command to the beginning of the batch file et voilà!

I've got a .NET assembly that was provided by a manufacturer that controls some hardware. We are calling the higher level .NET functions from Labview and they work. But we aren't getting acceptable performance for the high level calls, so we are trying to drill down into the lower level calls.

One of the .NET methods requires an ICollection<T> input, there in this case T is a channel object that is created elsewhere. The ICollection function is described the in the MSDN article: http://msdn.microsoft.com/en-us/library/92t2ye13

For reasons I don't really understand, Labview doesn't apparently support a constructor to ICollection. Something about Labivew not supporting calls to .NET generics, but I'd be lying if I said I understood that. But it seems like it should be possible to create a .NET assembly that creates a reference to an ICollection .NET object that can be passed to Labview. But I can't get it to work.

I've written a simple program that contains two methods. The first method GetUInt32 simply returns an input integer and was written as a test to see if I could write and assembly and call it from Labview. It works great.

The second method, GetICollection, is a test case to create a collection of UInt32 integers. Should be really simple, but it generates a compiler error. I suspect I'm doing something really basic incorrectly, but I'm at a loss to understand what. Can someone point me in the correct direction?

In one of the posts I saw something called as "PIPES" which is a part of Labview for Linux version.(which was seen under "Connectivity->Libraries and executables)

Is the same thing available on Labview for Windows also? How can i get the same?

I got an old LabVIEW 8.2 VI that use ITreeView under Windows XP. It works fine.
Now I have upgraded to LV15 and Windows 8.1 and I got an error "Library not registered in mxLT Open Tree Control.vi"

I would like register the library, but where do I find it? I have search the WEB but didn't find anything i could use(or understand;))
Edit: I found this "mscomctl.ocx" under SysVow64. 
I have registered it, but LabVIEW still say it's not registered! Has it something to do with LV15 =32bit and "msconctl.ocx" is in 64bit system folder?

Here is the BD of "mxLT Open Tree Control.vi":

Hope someone can give me a clue:)

Thanks in advance

/Bjarne

My questions are

1) How do I properly size DSNewHandle to fit the serial number, or is there no need to since it's a pointer which will just be set equal to the address of s_deviceInfo -> serialNumber

2) how do I assign each new 'h' to 'arr'

3) since the number of devices/serial numbers can vary, can I still manage this on the LabVIEW side by passing in an empty array constant as 'arr' to the dll? Or do I need to modify how I'm doing things?

I am a .dll  that act as interface with my HID device and Windows API.

I am a problem to open a connection with my device using the CLFN. But if i run the example, that is made with VC++, that is provided from  the Author of the .dll, the function return me the error code: "Device not Found"

The function and prototype in the DLL is:

FT260_STATUS FT260_OpenByVidPid(WORD vid, WORD pid, DWORD deviceIndex, FT260_HANDLE* pFt260Handle)

FT260_STATUS is an enum that i defined it as uint8 enum in labview

This is how I configured the CLFN:

uint8_t FT260_OpenByVidPid@16(uint16_t Vid, uint16_t Pid, uint32_t DeviceIndex, uint32_t* SessionID)

Convenction call is: stdcall (WINAPI)

Can someone help me to understand what is the problem?

Thank you very much

I'm trying to convert a local file path c:\... to a URI path file:///wdcwdc%20wdcwc...

Windows MPR.dll (C:\Windows\System32\mpr.dll) does that conversion using WNetGetUniversalNameA

https://docs.microsoft.com/en-us/windows/desktop/api/winnetwk/nf-winnetwk-wnetgetuniversalnamea#see-also

For some reason, I don't get the prototype to work using the call dll function.

Help will be much appreciated.

I am currently trying to create an HTTPS server with LabVIEW.

I have been using the built in TCP VI's for communication with the server and client, however I would like to use SSL or TLS in order to encrypt the data that is being sent across the connection. I know that I can point to either the self-signed cert that comes packaged with LabVIEW, or the certificate that we have for our server on-site.

I'm fairly certain that I can achieve this by building an assembly in .NET, and then using it in LabVIEW. I have looked around for TCP with TLS libraries for LabVIEW but could only found some out-of-date ones that didn't work with the newest version of LabVIEW. Do these libraries exist somewhere? And if not, is the .NET approach a solid idea?

Thanks,

Brandon Jones

TL;DR: My goal is to programmatically carry out whatever happens when I right click on an ActiveX container and choose the option 'Insert ActiveX Object...'. Ideally, I would like to avoid using VI Scripting to do this, but I haven't gotten anywhere so far and so really any solution will be a step forwards.

My most recent attempt (I'm using NI's Actor Framework) has been to place the ActiveX container on an Actor Core panel, then use Pre-Launch Init to open a Static VI Reference, and resize the front panel, with the container set to scale with the front panel. This doesn't work, because the static reference doesn't refer to the same thing that the AF then opens using the Launch Actor VI, but ignoring that problem, it also doesn't help with resizing the container.

Previously, I manually resized the container, but this I could only do after it was in existence, and so the object was already inserted.

My current observation seems to be that after I choose the ActiveX object to insert, there is little/nothing I can do to change the size of the object (I can change the container, but this doesn't do anything to the object - probably the object isn't very friendly-ly coded, but I can't do anything about that...). Consequently, I come back to my goal, which is to call some Invoke Node or similar, to 'Insert ActiveX Object...'.

Is there some way to do this? I don't intend to do it often, so long execution times, recompilation of VIs, shooting a cow over the moon are all fine if needed.

I need to implement this simple data casting of c# objects in LV

    object o = "MyString";
    SqlString t1 = o as String      

How this can be done in LV??

cast.vi

Notice: I left the error terminals untouched and none of the wires are connected (try it yourself). This never occurred to me. Only now, while hunting a null reference exception I found the constructor node looked "off", like this:

The strange part is that the terminal doesn't actually carry the reference (which is why I receive the null exception). It only specifies the type. The upper left terminal is a void type input, so the wire is always broken.

Does anyone know why these extra terminals exist? They don't seem to be part of the specification as far as I can tell.

Any fancy things we can do with this?

typedef struct tagZCAN_CHANNEL_INIT_CONFIG {
    UINT can_type; //0:can  1:canfd
    union
    {
        struct
        {
            UINT  acc_code;
            UINT  acc_mask;
            UINT  reserved;
            BYTE  filter;
            BYTE  timing0;
            BYTE  timing1;
            BYTE  mode;
        }can;
        struct
        {
            UINT   acc_code;
            UINT   acc_mask;
            UINT   abit_timing;
            UINT   dbit_timing;
            UINT   brp;
            BYTE   filter;
            BYTE   mode;
            USHORT pad;
            UINT   reserved;
        }canfd;
    };
}ZCAN_CHANNEL_INIT_CONFIG;

CHANNEL_HANDLE ZCAN_InitCAN(DEVICE_HANDLE device_handle, UINT can_index, ZCAN_CHANNEL_INIT_CONFIG* pInitConfig);

Can anyone give me some tips on how to pass this structure with union into DLL?

Thanks for any help you can provide!

I'm trying to use a library to interface some LVDT gauges from Marposs. It's implemented through COM objects and I have it working in Excel with VBA with this code:

Private Sub CommandButton1_Click()Dim oSmaoMain As SMAO.SMaoMainDim clsInfo As SMAO.InfoDim sInfo As String'Initialize the SMAOMain ObjectSet oSmaoMain = New SMAO.SMaoMainoSmaoMain.Initialize'List all the Installed DriversFor i = 1 To oSmaoMain.DriversCount   sInfo = sInfo & "Driver Name : " & oSmaoMain.Driver(i) & " " & oSmaoMain.DriverDesc(i) & vbNewLineNextMsgBox sInfo, vbOKOnly, "Installed Drivers"'List all the Enabled DriversSet clsInfo = oSmaoMain.InfosInfo = ""For i = 1 To clsInfo.DriversCount   sInfo = sInfo & "Driver Name : " & clsInfo.Driver(i) & " " & clsInfo.DriverDesc(i) & vbNewLineNextMsgBox sInfo, vbOKOnly, "Enabled Drivers"Set clsInfo = NothingSet oSmaoMain = NothingEnd Sub

When I port this code to LabVIEW I get answer from the SMAO.SMaoMain, correct initilization and even I can read the main objects properties. The problem comes when I try to access it's child object SMAO.SMaonMain.Info. When I get the reference and I make calls to the methods/properties, I get different results, always 0 drivers enabled.

I've attached the LabVIEW code I'm using and some captures of the creatable objects I can see from LabVIEW.

Any idea of what could be happening?

But when I compile the application into an executable, the xnode returns an error 7.  It appears the DLL is returning a valid pointer, but the xnode can't dereference it.  My hunch is that the pointer is crossing some kind of protected boundary, but I don't know for sure.

I suppose I could write a wrapper around the DLL call, but I really don't want to have to do that if there is a simple workaround.  Any ideas?

For one of the functions, according to the header file .h there is a structure data with parameters of different types that I have to pass to the dll. Some of the parameres are BYTE (1 Byte)  and WORD (2 Bytes).

When compiling this kind of structure with Visual C++ and looking at it's size with "sizeof()" it seems to me that 4 Bytes variables have to start in a position multiple of 4. For example if there is a BYTE and then a DWORD, the 3 Bytes after the BYTE are ignored and the DWORD starts at Bytes 5 to 8.

When defining a LabVIEW cluster to match the DLL structure, will LabVIEW do the same? If in my cluster there is a U8 variable and then a U32, will anyway the U8 take 4 bytes?

Thank you.

Trying to call the function below:

typedef struct
{
    unsigned int  Length;
    unsigned int  Id;
    unsigned int  TimeTag;
    char    Data[1024];
}DATA_FRAME;

int __stdcall SRVIVR_API_StoreData(void* handle, int partition,  int totalFrames, DATA_FRAME frameData[]);

Here is what the import dll tool produces:

This does not look correct to me and produces the dreaded 1097 exception error.

I modified the call to be:

Which I believe is closer to the intent of the original C function, but still gives me a 1097 error.  I suspect

that somehow the array pointer that the function is expecting is not correct.  The frameData parameter is being passed

into the function as a 'Adapt to Type', Array Pointer.  I also tried flattening to a single U32 array and passing that in as an array data type but still no joy.  Any ideas?

BTW, I have had success calling many other functions from the dll of the form:

int __stdcall func(void* handle, int param1,  int param2, etc);

So I launch the system and things seem to work at first - my DLL actually gets called and relays data from the 3rd party DLL to a Labview Event structure.  What seems to be happening:  Getting a valid function pointer to 3rd party DLL, getting the event trigger in my DLL, properly calling the Labview user event structure using data allocated with Labviews native memory functions.  BUT, then I get memory access crashes.  So my question is, do you guys think this is because Labview is trashing (deallocating) my DLL callback function rendering the pointer invalid after a certain time??  And if so, is there a way to prevent this?  And or, should I be taking a different approach and actually create a wrapper where the 3rd party DLL is called from within my DLL?  

When I call the DLL, there is a structure:

struct Signal
{
uint32 nStartBit; 
uint32 nLen;
double nFactor; 
double nOffset;
double nMin; 
double nMax;
double nValue;
uint64 nRawValue;
bool is_signed; 
char unit[11];
char strName[66];
char strComment[201]; 
};

There is another  Message structure to the above Signal:

struct Message
{
uint32 nSignalCount; 
uint32 nID;
uint8 nExtend; 
uint32 nSize; 
Signal vSignals[513]; 
char strName[66];
char strComment[201]; 
}

  The point is  Signal vSignals[513];

I've tried to solve it like this，but the program will crash.

How to create struct Message ，any good suggestions?  Thanks a lot.

message.vi

I want to be able to extract the text from PDFs from within LV. I thought this might be a common requirement but searching for "PDF" here returns nil, and Googling fairs little better. I've discovered that extracting text from a PDF is probably not easy in any language: the text seems to be contained in a very heavily encoded data stream. I doubt I could write an LV algorithm that could do the extraction well (or even badly, for that matter). My thoughts turn to interfacing with an existent DLL. Numerous PDF to text DLLs exist on the Web but I don't know C and its variants so don't really understand DLLs, to be honest.

A compay called Softinterface seem the most likely key to success. They've got some good stuff. I've had a play with some of their DLLs and the LV Import Library wizard which created some VIs but I couldn't get them to do anything (oddly, the header file for the DLL only defined very few of the functions that the DLL appeared to support).

I eventually got something going via the afore mentioned comapany's product ConvertDoc. This is a PDF to text GUI application that has a command line. So, I send the command line paramaters to it via the System Exec VI calling the cmd console. It extracts the text from the PDF and writes it to a text file (not surprisingly). LV then reads the text file and does what I want with the text.

So, I can do it but only with the clunkiest of methods. Can anyone point me in the direction of a slicker method of extracting the text from a PDF? Many thanks in anticipation.

Regards, Graeme.

Where this breaks down is when calling a LabVIEW exe from the console, the console thread is not blocked while the exe runs. So, the result is the console returns back the command prompt and then a little while later my exe sends the data to the console and it just appears where ever the cursor is currently at.

So, I need to figure out a way for my exe to steal the thread of the console and block it until it is done writting its output.

Any gurus out there have a idea even where to start figuring this one out? It has me baffled.

BTW: if you also have a .NET solution for writing to the stdout instead of the old school kernel32.dll solution, I would love to see it.

thanks for the help and/or sympathy.

-John

PS. If you are wondering why the *$@#$! anyone would want to do this, basically it comes down to the need for some non-LabVIEW DEVs to control some cFP hardware over Ethernet and the only way I know how to do this is using LOGOS via DataSockets and that only works in LabVIEW!

It would appear this is something related to the OS because the exe works on the dev machine - just not the target.

Any suggestions would be greatly appreciated.

Chris

In my project, I have to use other application which wasn't developed with LabVIEW.

My problem are:

1, How to set value to controls from its UI?

2, How to get data of its indicators?

3, How to simulate mouse actions, left-click and right-click?

4, Important, I'd like the UI is hidden.

Now I can do 1, 3 with its UI displayed, I can't do 2.

Someone recommended a tool named "autoit", but I have no idea about how to start it in LabVIEW.

Personally, I prefer to achieve my target with some windows dll or activX, etc.

The object's method returns an array of array of any() type. it seems LV can't compile this, even though the wire appears not to be broken. If I try to parse the array of array into a single dimension and then rebuild, the code is broken. See the attached files. Is there a solution for this issue? The alternative would be to copy cells one by one, which is a much slower solution.

BUT I'd like to do the same on Windows Embedded Compact 7.0 with ARM(Cortex-A8).

When I build the DLL project on "Smart device / WindowsCE" platform it compiled successfully but the linker stopped because "NumericArrayResize" is unresolved symbol ... I think the reason is that the "labviewv.lib" generated for x86 architecture not for ARM.

So my question is: Is there any libviewv.lib for ARM platform?

http://beltoforion.de/article.php?a=muparser&p=interface

For example, I created an array of double, bundled it and plugged it into the DLL.  The parameters of the DLL are "Adapt to Type". The prototype in Labview is "void  pointertest(void *source);"

The C program:

// dllmain.cpp : Defines the entry point for the DLL application.
#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include "Header.h"

extern "C" __declspec(dllexport)void pointertest(LVCluster *source);

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}
void pointertest(LVCluster *source) {
    source->dimSize = 2;
    source->arg[0] = 3.1;
    source->arg[1] = 4.2;
}

 The header: Header.h

#pragma pack(push,1)
typedef struct {
    __int64 dimSize;
    double arg[2];
}LVCluster;
#pragma pack(pop)

The LABVIEW VI is attached.  I checked the foren. However, I cannot figure out what I did wrong. Please give me a hint.

Your support is highly appreciated.

pointertest.vi

I have a big project, pretty much already coded in Labview, designed to perform monte-carlo analysis on a set of applications that use data from time synchronized measurements across the electrical power system.

The project is designed to be open source and distributable using both built .exe and vipm.  Therefore I include ONLY libraries that either come with LV or are OpenG (no third party tools that need to be purchased, and no TestStand).

A part I have yet to code is the monte-carlo engine which needs to be end-user programmable.  I have an idea for creating my own set of commands and a labview interpreter, but before I do that, I'm thinking that many of my end users will already have some python ability.  So I'm trying to decide to use labPython.  The problem is that I have not found any documentation or examples for it yet.

What I need to do, is have the python script, written by the user, access controls (mainly clusters or 2-D tables), overwrite the LV control values, then start a test run.  This is essentially test automation.  Python would be nice because then the user can use local variables to calculate the values to be written into the controls.

So I'm looking for your advice:  Should I give LabPython a try?  If so can someone:

1) point me to some documentation

2) point me to some example code (especially how to access controls).  

3) tell me where to go when I need to ask for help (this forum or another)

Thank you so much.

I did a

1. C++ project,
2. generate DLL
3. and I call it from VI.

It's working on my pc but if I make an application for another pc, the application works but the dll is not working. I installed the c++ redistributable on second pc but I had the same problem.

in particular a message error with "error 42" appears. Can you suggest me some check to fix it ?

thank you very much for your collaboration

On the other hand I wrote a simple c# code and I am able to call the dlls with the respective methods. I believe it is the third party unmanaged c++ which is causing the problems. Do I need a dll wrapper for this to work?

Ton

Write Table to Excel with DotNET.vi

   I have a .dll running in LabVIEW, the developer of the .dll is writing all of the data to the standard output (_stdout). I need to be able to read this output with LabVIEW.

I have already been pointed to an old post in the NI Forums:

http://forums.ni.com/t5/LabVIEW/Redirecting-stdout-stderr-stdin-to-from-LabVIEW-in-dlls/td-p/1768662

This post is old, and the solution does not work in anything about LabVIEW 2012 (and I need it to work in 2015)

Does anyone know how to display/read the _stdout from a .dll in LabVIEW.

Cheers, Alec

I'm trying to get some script running in labpython.

the code is the follwing

=====================

=====================

The code works perfectly when called from python25.exe or 27 but when called through the Labpython interface fails claining "socket" is not defined.

I'm pretty sure the instruction is sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM) but I can't understand why.

===================

PYTHON Execute Script__ogtk.vi->PYTHON sandbox.vi:<type 'exceptions.NameError'>, global name 'socket' is not defined

===================

Any suggestion would be more than welcome.

The same instruction works fine when called directly and not inside the tcpalinks tcpalinks.

Best Regards

Filippo

I have a fresh instalation of LV2015sp1 32 bit, on top of that I've installed the OpenG Toolkit 4.0 and LabPython 4.0.0.4. I have Python 2.7 (Anaconda2 2.5.0) installed as well.

Everything seems to be fine, as long as I use some simple script, but when I try to use a script involving e.g. numpy then the whole thing freezes at execute_script.vi

What I might be doing wrong?

Title says it all. I'm a newbie to Python (and thus to Labpython) although not to LabVIEW. I've got a friend who is a Python genius but a newbie to LabVIEW. He's written me an algorithm in Python that i want to run in Labpython before trying to check it out before implementing it in LabVIEW (or i may just leave it in Python). Problem is we keep on getting errors and between us have no idea what is wrong. I cannot find any documentation on Labpython or examples (except for one here).

What i need is a bit of Python code (some advanced stuff would be great) that runs succesfully in Labpython so that my friend can take a look and see the format/style/method of writing python code for Labpython).

Could someone point me in the right direction either with a bit of code or some sort of documentation to help?

Thanks

Phil

DWORD WINAPI CredUIPromptForWindowsCredentials(
_In_opt_    PCREDUI_INFO pUiInfo,
_In_        DWORD        dwAuthError,
_Inout_     ULONG        *pulAuthPackage,
_In_opt_    LPCVOID      pvInAuthBuffer,
_In_        ULONG        ulInAuthBufferSize,
_Out_       LPVOID       *ppvOutAuthBuffer,
_Out_       ULONG        *pulOutAuthBufferSize,
_Inout_opt_ BOOL         *pfSave,
_In_        DWORD        dwFlags
);

I've been told that Rolf would be able to solve this in 30 seconds.  Help me LAVA! You're my only hope!

   I need to authenticate users on my program relying on LDAP.

At the moment i use a .NET contructor that work but it takes 30 seconds to authenticate the user.

Is there any other way to do this?

Activex? dll? 

Thank you!

Attached you can find the snippet of the way i do now.

typedef struct
{
	LVBoolean status;
	int32_t code;
	LStrHandle message;
} LVErrorCluster;

template<typename Func> int64_t ExceptionGuard_LVErr(Func&& guardfunc, LVErrorCluster *LVError)
{
	try
	{
		return guardfunc();
	}
	catch (WrpExcUser &e)
	{
		return CopyErrorUS(e.whaterr(), e.what(), LVError);
	}
	return NOERROR;
}

//then use the guard like this in a LabVIEW CLFN call

int64_t ErrorTest(LVErrorCluster *lverr)
{
	return ExceptionGuard_LVErr([&]
	{
		throw(WrpExcUser("Some funky user error", -6426429678568));
		return NOERROR;
	}, lverr);
}

But my code doesn't catch just the WrpExcUser exception, but also generic stuff like std::bad_alloc, std::bad_function_call that can occur within the guarded section of code and makes them into some user friendly messages instead of the standard "exception occured -1xxx message". Is it legal to catch these exceptions? I wanted to keep my CLFNs error checking to default.

Now, something I do not know, can I call DLL_A functions directly from within LabVIEW or do I need to wrap all the DLL_A functions as well?

I suppose my question is more like, when LabVIEW loads my wrapper DLL, do two copies of DLL_A exist in memory?

Does anybody know how to set the menubar colour in an application? I have done some digging and it seems this is possible using the windows API, just wondering if LabVIEW had some way to do this natively? (I doubt it, just thought I would ask).

I am trying to figure out, if it is possible to create a native LabVIEW I/O interface to C/C++ code, that is using the I/O functions through callbacks.

The scenario is as follows:

I made a toolkit to process multimedia formats and (so far only) video codecs, it is using internally FFmpeg shared objects (DLLs or SOs, further just "DLLs").

They way the FFmpeg DLLs access I/O is through callback mechanism. Following all happens in the wrapper.

If I want the toolkit to read data from some I/O like network or disk, I have to create a session, and part of the session are function pointers to callbacks doing various tasks, one of them is reading data.

Anytime a user tries to read more data (1 data packet), he forces a call to the session demuxer, that further uses the I/O callback so long, until it parses one packet/hits EOF/corrupt data/etc..., now this works nicely if you want to provide data through standard means like video file or stream URL.

Since the capabilities of FFmpeg allow for example (de)muxers and codecs for images, I thought it would be cool to give the user possibility to supply his own data, that he reads via LabVIEW from database or whatever. Not just limit the usage of I/Os implemented inside the DLLs.

All I know, is that I cannot use VIs as callbacks inside C/C++ code, so the only way is to somehow "decallback" the implemented I/O mechanism. 

My company is starting a project where some Matlab files (.m) need to be executed by LabVIEW. The 2 obvious solutions are Matlab script nodes and MathScript nodes. Unfortunately, even though the latter one is the most cost-effective and light in terms of installation, many of the functions we need are not supported by the Run Time Engine, so it's kind of a deal breaker.

For the Matlab script nodes, I know Matlab needs to be installed since LabVIEW will request Matlab to execute the scripts through ActiveX. What I don't know is: what version of Matlab? Is there a cheaper "Run Time Engine" of Matlab we can use instead of buying the full-blown developement version of Matlab?

Any other comment, remark, suggestion, alternatives?

Thanks!

I have to call the following function that is part of a C dll:

icon_regfilt_createRegistrationFilter (const char * extractComponent, const char ** extractSubcomponent, const float * shifts, unsigned int nSubcomponents, enum regfilt_interpolation_method_t method, BOOL copySubComponents)

How can I pass the extractSubcomponent parameter, that is an array of strings (char**)?

In C it is quite simple, this is how the function is used:

char * registrationDataFormat;

char* extractionDataFormat;

const char* subComponents[3] = {"Red", "Green", "Blue"};

float shifts[3] = {0.0f, 0.0f, 0.0f};

// Create a registration filter for the component named Color 1

registrationFilter = icon_regfilt_createRegistrationFilter("Color 1", subComponents, shifts, 3, NN, FALSE);

In LabVIEW I tried a few:

- create the array of strings in LV and pass it directly to the call library node declaring it as "Adapt to type" and "Handle by value"

- create the array of strings in LV and pass it directly to the call library node declaring it as "Adapt to type" and "Pointer to handles"

- converting in LV the array of strings to a 2D array of numbers and passing this to the Call library function node (but I can't change the function in order to pass the array sizes)

but the problem is that in LV 8.5 it always crashes and in LV 2010 the function runs and returns a pointer as it is expected, without any error, but actually it doesn't create the memory structure that should create.

Have you ever passed an array of strings to a dll? How can I do this?

Thank you very much for your help!

 I wrote an application which can use either a 32 bit or a 64 bit dll, it loads the dll from a path specified in an INI file. This code works properly on the development machine (LV2013, both 32 and 64 bit, both with a debugger and as an EXE) but doesn't work on the tester machine as an executable. It throws error code 13 (in LV2013 - file is not a resource, in LV2014 - Failed to load DLL due to invalid format or missing dependencies). 

However, when I change all the Invoke nodes to use a static predefined path, everything is OK.

What am I doing wrong here? I rather maintain one code base and build for each target than maintain a code for each target.

The API dll is from signalhound.com http://signalhound.com/spike

http://nlog-project.org/documentation/v4.0.0/html/T_NLog_Conditions_ConditionExpression.htm

There's an Operator that will convert a string to the Condition object that I need as an input to the ConditionExpression. But, since you can't call that in LabVIEW, anyone have any ideas on how to get around that? I suppose I could write a quick .dll myself that inputs a string and outputs the appropriate Condition object. Just didn't want to go down the path if I didn't have to.

(im sorry if this post is more a c/c++ code porting problem than a actual labview problem, but... )

I just bought myself a brand new apple Mac book Pro, 15" with OS X Leopard (10.5.X i think?) installed.

After playing around and familiarizing my self with mac, OS X and its unix like environment, i decided to port some of my labview code wrappers that we use at work to interface with various things, previously compiled for both windows in visual studio 6 and 8 and linux red hat 4 and 5. (gcc 3.4.2 and gcc 4.1.2 i beleive, but not 100% sure).

So i did some reading, and it seemed that on mac a ".dll" from windows and ".so" from unix/linux on OS X is called ".dylib". i installed the Xcode package, labview 8.6 for mac, and some other stuff that might come in handy.

After modifying my makefiles (basically replasing -shared with -dynamiclib and recompiling with gcc in the terminal) i tried to load the new "myFile.dylib" in labview.

Unfortunately labview didn't read any of my callbacks, and the dropdown list where you can choose function in the "call library node" was grayed out or empty.

so not knowing what whent wrong i made a small "cout" callback like this:

############# myCout.cpp #################

#include <iostream>

#define API __attribute__(( __cdecl__ ))

extern "C" void API Cout(char * myCout)

{

std::cout << myCout << std::endl;

}

################ Makefile #################

CC = g++

# Backup files from various editors ...

BAKS = ,* *~ *.bak *.BAK .es1* .B* %*% .ec1 .ek1 .*~ core a.out *JNL *.lst \\\#*\\\# .nfs* *%

#

CFLAGS = -g -c -I/usr/include -o $@

LDFLAGS =

OBJ =

LDLIBS =

#

all: cout.so

#

cout.so: cout.o

@-$(RM) $@ $(W)$@

$(CC) $^ $(LDLIBS) -o $@ -dynamiclib //only changed this on mac

#

cout.o: cout.cpp

$(CC) $(CFLAGS) cout.cpp

#

clean:

$(RM) *.o $(BAKS)

making the .dylib went fine. no errors, and no warnings. but still I'm unable to load this library and use its function in LabVIEW.

What am i doing wrong??

Any help would be highly appreciated.

X

Update: I realized after some searching that i can't use "dylib" in mac, but have to use something called ".framework" (bear with me cos this is all new to me ) so then i hoped all i had to do was replacing the "-dynamiclib" with "-framework" and name the output xxx.framwork, but now it won't compile (said something about "argument to -Xlinker missing" )

guess it's time for bed and try with some fresh eyes tomorrow.

int sqlite3_open(  const char *filename,   /* Database filename (UTF-8) */  sqlite3 **ppDb          /* OUT: SQLite db handle */);

I am passing some data from dll to labview. It is an array of clusters. Cluster looks like this:

typedef struct 
{
	LStrHandle longname;
	LStrHandle name;
	uint8_t intraonly;
	uint8_t lossless;
	uint8_t lossy;
} CodecInfo, **CodecInfoHdl;

typedef struct CodecInfoArr
{
	int32_t dimsize;
	CodecInfo Arr[1];
} CodecInfoArr, **CodecInfoArrHdl;

But I think it is reproducable with any kind of array of clusters where are other handles, like LStrHandle in my case.

The operation is pretty straightforward.

I check the incoming handle, I handle the situation where it is empty or filled with data and in the next step I have an empty handle to work with.

So far I have an array handle returned from DSNewHandle allocated for the resulting array size.

I start copying the data, but since there are strings involved, I call my general char2LStrHandle function to fill string handles.

void PrintChar2LVStrHandle(const char *charstr, LStrHandle *StrHandleP, bool forcenew = false)
{
	MgErr error = mgNoErr;
	std::string temp = "";
	if (charstr)
	{
		temp.assign(charstr);
	}
	if ((!IsHandleEmpty(StrHandleP)) && !forcenew)
	{
		error = DSDisposeHandle(*StrHandleP);
		if (error != mgNoErr)
			throw(WrpExcUser("PrintChar2LVStrHandle()", error));
	}
	*StrHandleP = (LStrHandle)(DSNewHandle(Offset(LStr, str) + sizeof(uChar)));
	if (*StrHandleP == nullptr)
		throw(WrpExcUser("Could not allocate string handle", CUSTOMERROR));
	//(**StrHandleP)->cnt = 0;
	error = LStrPrintf(*StrHandleP, (CStr)"%s", temp.c_str());
	if (error != mgNoErr)
		throw(WrpExcUser("Could not print to string handle", error));
}

There is a lot of junk&unnecesary code, but the core of the function is to check the handle, and if it is valid, just print into it. The function that checks the handle looks like this:

bool IsHandleEmpty(const LStrHandle *h)
{
	MgErr err, heaperr = mgNoErr;
	err = DSCheckHandle(*h);
	//heaperr = DSHeapCheck(0);

	if (err)
		return true;
	return false;
}

It is just a stupid wrapper around DSCheckHandle. 

Now the problem is, that with the way the array handle allocated the array elements, some handle pointers, from time to time point to memory so unfortunately, that the array elements that get processed later have string handle pointer pointing to memory that is already filled with data from previous array filling loop iterations. It is not the exactly same memory, since the data is little off (garbage, count is wrong etc.), but it is sufficient enough for the DSCheckHandle return, that the handle is valid. So the memory gets a treatment like it would be a real handle and it corrupts the labview heap, so when the data gets deallocated, LabView / runtime will crash.

So far I tackled the solution with simple optional parameter (bool forcenew = false) and went through all the function references in code to set the flag if the data comes from new array handles.

Finally the question: Is there more elegant solution to this, somehow correctly check the incoming string handle ?

Is it possible to pass a LabVIEW cluster to/from a .NET invoke node?  

I have complete control over both the .NET and LV code, but I have not been able to find a way to do this.

I am writing a LabVIEW API based on a 3rd party DLL. The DLL function I am working on right now returns a string and 2 U32. The string is only an output, but the 2 U32 are used as both inputs and outputs. So long story short the 3 parameters are defined as pointers. The 2 U32 work as specified in the documentation, one of them (psize) returning the number of characters that the string is supposed to return.

However I can't get the string properly. The documentation tells me that it is a C String and I configured the parameter as such, but when I run the function I get only the first character of what I'm supposed to get. The next test I made (see below) returns all the other characters except the first one and helped me understand why this first test returned only the first character: the string is Unicode! This means that each character (though able to be represented in ASCII) takes 2 bytes, one of them being the null character. And since a C string ends when the null character is encountered, this explain why LabVIEW only gives me the ASCII value of the first character.

In the second test I'm talking about, I modified the parameter to be a Pascal String Pointer instead of C String Pointer. I got all the characters except the first one, which makes sense I guess since the first character is the length in a Pascal string.

Basically so far I haven't managed to find a way to read the whole string in one call. I would love to find a solution where I just ask for an array of bytes and just perform my own parsing, but the DLL returns an Invalid Parameter error when I try it.

Have you run into something similar? Do you have any tips?

Help would be much appreciated!! (on top of this issue, LabVIEW crashed 50% of the time  )

But unfortunately am getting this error straightaway when creating a new session...

Is this a show stopper or is there some hope to work around this?

http://sourceforge.net/projects/pybywire/

I gave it a go but without an example or docs could not really make heads or tails of its capabilities.  It has a good pedigree since it is written by the same person who developed the zmq libraries. 

The problem is that the event data is a struct with a DWord and a few floats or doubles and for some reason when we try to create an equivalent LV cluster (a U32 and SGLs or DBLs) the first integer gets through fine, but the floating points values are completely meaningless.

We also did a quick test with a cluster with just three INTs and we still only get the value for the first one - the other two are always zero.

I don't have the code at the moment (and it's too messy anyway at the moment), but does anyone know what would be the correct C/C++ code to get the event reference from LV (although that part seems to work fine) and to send an event of a struct with a few scalars (preferably with doubles as well)?

https://decibel.ni.com/content/docs/DOC-1133

but it no longer compiles and it does not seem to correlate any longer with the current IronPython .net asembly.

I've been having alot of problems with calling SDK funtions. Is there any resources that clarifies the funtion parameters and how to configure them in labview.

found this link These are the some of the dll's I need to call.

One of the things I'm tring to do is find USB devices. The first thing I need to do;

-call the SetupDiGetClassDevs which is in the setupapi,dll. see link

SetupDiGetClassDevs returns a handle to a device information set that contains all installed devices that matched the supplied parameters.

Depending what I set for parameters i can get imformation on all devices connected to all ports.

My problem is don't know how the parameters are configured.

HDEVINFO

SetupDiGetClassDevs(

IN LPGUID ClassGuid, OPTIONAL (how do I configure each of the parmteters in labview)

IN PCTSTR Enumerator, OPTIONAL

IN HWND hwndParent, OPTIONAL

IN DWORD Flags

);

There are more call I need to make ,but need to get this imformation first.

Thanks