Calling DLL function using LabVIEW 7.1?

Here's the scinario:
I have LabVIEW 7.1 and i'm trying to call a DLL function using 'CALL LIBRARY FUNCTION NODE'.
I have used this in the past with no problem. But right now, when I use this node and link it to the
library and function name, i get 'ERROR loading Dllname.dll' message.
NOTE that the DLL is generated using VStudio2003 or VStudio.NET. Could this be a problem??
Also, i noticed that there are some JUNK characters before & after the function name that show
up in function prototype:
long ?EcpvsSign@@YAHHPBEH0HPAE1@Z(long Signer, CStr NonRMsg, long NonRMsgLen,
CStr RMsg, long RMsgLen, CStr SigR, CStr SigS);

tbd wrote:
Hi rkpat,
You might check-out this thread on building WIN32 DLLs - expecially the bit re: "mangles names" under the paragraph titled "C Language Source File". My recollection is that 'extern "C"' directive in the header file for the DLL solved the name-mangling problem, but it's been a few years!
Cheers!
Message Edited by tbd on 03-01-2007 11:19 PM
tbd is right. You have to first disable name mangling as it creates all kind of troubles. Other issues might be that your Visual Studio 2003 or .Net edition links in dynamic runtime libraries that are not standard available on every Windows PC so that you need to redistribute the according runtime library installer together with your app for the DLL to be even loadable.
Rolf Kalbermatter
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Similar Messages

Labview Dll call library function Causing Labview to unload

I am trying to use the Call Library function in Labview 7.1 to call an Init function for a Zathic Can4USB device. When I run the vi, it complete log LabView out of the computer. Can anyone tell me why the function totally unloads LV without displaying an error?
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Either the function has a serious bug or you are calling it with
invalid parameters or wrongly setup parameters. The problem happening
here is that your DLL passes somehow invlid parameters to a system
device driver and that driver causes a protection fault. For device
driver execeptions which happen in the privileged kernel, Windows does
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Check the documentation for this function and try to see where you call
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Rolf Kalbermatter
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

I am trying to call a function with LABVIEW developed in CCS compiler

I used MPLAB (CCS compiler) to develop c code that is used to transmit and receive messages to and from an automotive display. It works great as a stand alone. I would like to call this function from LABVIEW but am having difficulty doing so. Does anyone have experience calling a MPLAB developed project from LABVIEW? Thanks in advance.
Matt

PTE wrote:
I used MPLAB (CCS compiler) to develop c code that is used to transmit and receive messages to and from an automotive display. It works great as a stand alone. I would like to call this function from LABVIEW but am having difficulty doing so. Does anyone have experience calling a MPLAB developed project from LABVIEW? Thanks in advance.
Matt
MPLab is for programming PICs if I'm not mistaken. I'm not sure how you would want to call a function compiled in MPLab from LabVIEW directly. MPLab will create binary code for execution on PICs and there is no LabVIEW that could run on a PIC. On the other hand I didn't think you could create standard Windows DLLs, Mac shared libraries or similar in MPLab at all.
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Rolf Kalbermatter
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a division of Test & Measurement Solutions

Application crashes when calling DLL built with LabVIEW 2011

Hello everybody,
Our application calls DLLs built with LabVIEW 2010 SP1. We installed LabVIEW 2011 and built some DLLs. So far so good. If we start our application and run 2010 DLLs it still works fine. If we run a 2011 DLL just once no error happens, but if we try to run the same 2011 DLL our application crashes reporting the error below. I saved the code for 2010 version and built a DLL and it works fine. Does anyone know why?
Thank you in advance.
#Date: Fr, 16. Sep 2011 16:25:25
#OSName: Microsoft Windows XP Service Pack 3
#OSVers: 5.1
#OSBuild: 2600
#AppName: PasTA
#Version: 11.0f2 32-bit
#AppKind: AppLib
#LabVIEW Base Address: 0x30000000
16.09.2011 16:25:26.181
Crash 0x0: Crash caught by NIER
File Unknown(0) : Crash: Crash caught by NIER
minidump id: 8a779b3f-51d7-4864-8e4d-6ab0195cd158
ExceptionCode: 0xC0000005
N
0x3072C804 - lvrt <unknown> + 0
0x3072CBB8 - lvrt <unknown> + 0
0x7C864191 - KERNEL32 <unknown> + 0
0x7C83AB50 - KERNEL32 <unknown> + 0
0x00000000 - PasTA <unknown> + 0
Attachments:
error.PNG ‏11 KB

On that note, you should be able to create DLLs in 2010 and run them with 2011, correct?? In my case, I have a 2010 built DLL (talking to sbRIO), most of the functions work when run in 2011, but a couple of them lock up LabVIEW on the desktop (but not the sbRIO), no lock ups happen with 2010 on the desktop.

Call DLL function with pointer to simple struct

Hello,
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Here is the function and his parameter:
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int major;
int minor;
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BYTE byBuffer[2048] ;
if( !Comm_BTE_readYMem( byBuffer,COMM_BTE_TX14_SOFTVERSIONADDR,
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//. process the answer
pVersion->major = (int) (byBuffer[0] & 0xFF) ;
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In attached file there is the Comm BTE soft Version.vi that try to access this function. The code crashes when the function is called and labVIEW is closed.
I probably don't pass the data parameters correctly to the CLFN.
Thanks for help.
Regards. NewCLAD.
Solved!
Go to Solution.
Attachments:
Comm BTE soft Version.vi ‏13 KB

Everything is configured correctly EXCEPT the numeric representation of the values in the cluster. They must match int, which is most likely 32 bits on your platform. In your VI, they are U8.

Can I call a function using array index?

I've defined an array which stores the function name, like this:
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Note: thumbTopClick() is a function inside which all these codes are written.
I need to find out whether it is posible in AS3 to call a function name using the array index or not. If yes, could you pleas ehelp me out.

Thanx Andrei1, you were right, i was out of range.The value of i will obviously expire outside the for loop. Now I have corrected my mistake by assigning the value of i to a variable index inside the for loop and then use the following code:
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Call DLL function from JAVA

HI!
What's the best way (and simple) to call DLL function from JAVA.
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Do a google search for 'JNI tutorial' and it will turn up hundreds of examples.

How to access Call Back Functions using *.dll in the Labview?

Hai,
I am Pavan Ram Kumar Somu.
I am new to Labview, currently I am working on MVB Interface.
I need to access the API functions from *.dll file in Labview, as of now , I am doing this with Call function Library node in Labview but it does not support the following data types like
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1. How to pass pointer arguments to API functions in DLL and how to collect pointer
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Examples:
I)
Unsigned short int gf_open_device(void *p_device_config, unsigned long int client_life_sign_timeout, unsigned short int *device_error)
void *p_device_config: How to access/pass these arguments in LabView and to which memory location it points in LabView.
II) #include <windows.h>
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     HANDLE rcvEvent0, rcvEvent1;
/* Function call*/
CanGetReceiveEvent(handle[0], &rcvEvent0);
Above is a piece of C code, Now I want to use HANDLE datatype which is windows based, how to use these type in the LABVIEW.
With regards
Pavan Ramu Samu

"Somu" <[email protected]> wrote in message news:[email protected]...
Hai,
I am Pavan Ram Kumar Somu.
 
I am new to Labview, currently I am working on MVB Interface.
 
I need to access the API functions from *.dll file in Labview, as of now , I am doing this with Call function Library node in Labview but it does not support the following data types like
    1. Pointer Arguments(To which memory it points in Labview)
    2. function pointers Arguments
    3 .pointers in structures and pointer structures in structures and many other data types.
 
Please Answer the below queries also:
 
1. How to pass pointer arguments to API functions in DLL and how to collect pointer  
    return types from API functions in DLL
 
2. How to pass structure arguments to API functions in DLL and how to collect structure
    return types from API functions in DLL
 
3. How to use callback functions(nothing but function pointers) in Labview and how to
    collect callback fuctions return types from API functions in DLL
 
I need your help while passing these datatypes to API functions in DLL from labview.
 
Suggest me if there is any other alternative for implementing this task.
 
 
I am referencing some examples here:
Examples:
I)
Unsigned short int gf_open_device(void *p_device_config, unsigned long int client_life_sign_timeout, unsigned short int *device_error)
 
void *p_device_config: How to access/pass these arguments in LabView and to which memory location it points in LabView.
 
II) #include <windows.h>
     #include <process.h>
   
     HANDLE rcvEvent0, rcvEvent1;
 
/* Function call*/
CanGetReceiveEvent(handle[0], &rcvEvent0);
 
Above is a piece of C code, Now I want to use HANDLE datatype which is windows based, how to use these type in the LABVIEW.
 
With regardsPavan Ramu Samu
Search the forum (forums.ni.com) for callback, pointer or handle, and you'll find that it is all possible, but not very easy.
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Regards,
Wiebe.

How to implement a callback function using LabView's Call Library Function Node?

I am trying to call a fuction from a SDK.dll library using the Call Library Function Node. The SDK was provided to
me and I do not have the source code, just the .dll and .h files.
The SdkSetPropertyEventHandler function has a callback fuction as one of its parameters. How do I implement the
callback using the CLF node? I am a good LabView programmer but this is my first time using the Call Library
Function Node. I have read all the info I can find on NI's web site and the discussion board but cannot figure
this one out. I am using LabView 8.6.
The SDK.h deacribes the function as:
// Function:   SdkSetPropertyEventHandler
SdkError SDKAPI SdkSetPropertyEventHandler(
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            SdkVoid*                        inContext );
// Description:
//       Registers a callback function for receiving status
//          change notification events for property states on a camera.
// Parameters:
//       In:    inCameraRef - Designate the camera object.
//              inEvent - Designate one or all events to be supplemented.
//              inPropertyEventHandler - Designate the pointer to the callback
//                      function for receiving property-related camera events.
//              inContext - Designate application information to be passed by
//                      means of the callback function. Any data needed for
//                      your application can be passed.
//      Out:    None
// Returns:    Any of the sdk errors.
A separate header file called SDKTypes.h contains the following data:
typedef SdkUInt32 SdkPropertyEvent;
typedef SdkUInt32 SdkPropertyID;
typedef void       SdkVoid;
typedef struct __SdkObject*    SdkBaseRef;
typedef SdkBaseRef    SdkCameraRef;
SdkPropertyEventHandler
typedef SdkError ( SDKCALLBACK *SdkPropertyEventHandler )(
                    SdkPropertyEvent        inEvent,
                    SdkPropertyID           inPropertyID,
                    SdkUInt32               inParam,
                    SdkVoid *               inContext );
Thanks for your help.
Alejandro
Solved!
Go to Solution.

alejandroandreatta wrote:
I am trying to call a fuction from a SDK.dll library using the Call Library Function Node. The SDK was provided to
me and I do not have the source code, just the .dll and .h files.
The SdkSetPropertyEventHandler function has a callback fuction as one of its parameters. How do I implement the
callback using the CLF node? I am a good LabView programmer but this is my first time using the Call Library
Function Node. I have read all the info I can find on NI's web site and the discussion board but cannot figure
this one out. I am using LabView 8.6.
Basically you do not do that. LabVIEW does not know pointers and certainly not function pointers. What you should do instead is writing a C DLL that implements the callback and also exports a function to be called by LabVIEW that translates between the callback and a LabVIEW user event. Look for PostLVUserEvent() here on the NI site to find examples how to do that.
Rolf Kalbermatter
Message Edited by rolfk on 02-11-2009 08:00 PM
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Can not find size_t during import a dll and calling a function crash labview

Hello, experts
I need to use FingerLakeInstrument DLL ( see the attached) inside Labview to talk to a CCD camera. it is built from microsoft visual studio C++
I unzip FLI dll in my D:\proj\...\linfli-32 and import dll from there. created a c:\FLIDBG.txt as FLI dll needs to write debug message to it if FLISetDebugLevel() or others are called.
During importing the dll, first thing I got is <sys/types.h> ( ie size_t ) cannot be found. I have installed free version of microsoft visual studio C++
but can not find "typedef unsigned int size_t"
at the end, I just added
typedef unsigned int size_t;
in the libfli.h. Having done that, I am able to import all functions into Labview and have a user library called libfli.
However, as soon as I start calling a simple function in a test.vi, such as FLIGetLibVersion(char* ver, size_t len), which involves nothing other than the library, the labview will crash.
I created a simple C test.exe which calls many functions without any problem
any suggstion?
regards
xiaofeng
Solved!
Go to Solution.
Attachments:
libfli-32.zip ‏93 KB

Hi, Smercurio_fc
thanks for your reply. Yes, you are pointing to the right place. I have solved the crash problem.
when importing DLL into Labview using Tools\import\Shared Library (.dll), Labview automatically set the calling convention as C not as stdcall (WINAPI). it is this that later the labview crashes when a function is called. as soon as I manually re-selecte calling convention as stdcall, my test.vi works OK (see attached).
I tried Call Library Function too to call libfli.dll, as long as I select stdcall as call convetion. the test.vi works.
How do I know which Call convention I need to choose if there is no infomation from DLL provider?
as for the size_t,
I add #include <crtdefs.h> in libfli.h and
add additional include path as
C:\Program Files\Microsoft Visual Studio 10.0\VC\include. this solved the "not found" issue.
for this case I know that the DLL is built from VC++, is this right way?
again, thanks for your time.
xiaofeng
Attachments:
test.vi ‏13 KB

Reading a line from a third party software using call dll function.

Hi,
I am using a third party software in Lab VIEW.
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I have the VI attached here, As u can see in the VI I am not sure how to use the function
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This has three parameters and they are
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What basically happens with this function is this...
/* ROUTINE LCOM_MasterGetLine
It Reads line of maximally Length characters from Slave ID into Buffer and the parameters are
* ARGUMENT(S) ID ... Slaves ID
* Buffer ... Where do you want chars (at least Length+1 in size)
*Length ... How many at most (should be less than LCOM_MAXLEN)
Can
any one help me how to define the input parameters for this function, for example in the fourth part of the Vi attached here.
What I understand from the function is that, the third party software when it sends a line, that line is stored in the input parameter...buffer ...that is defined to the dll.
Can any one help me how to then read what line has been sent from the third party software.
I am including the dll file and also the header file here.
Thanks a lot,
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Attachments:
New_Folder.zip ‏30 KB

One problems with your solution:
LCOM_MasterGetLine(int ID,char*Buffer,int Length)
You should allocate a buffer large enough in LabVIEW and pass it to the Call Library Node. The dll function needs som space to actually scribble in whatever it wants to do.
Check out the attachement this should more or less be what you will need.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions
Attachments:
ex.vi ‏45 KB

Can I call a User-Defined Mathscript Function using LabVIEW 7.1?

I am trying to use a User-Defined function call in a mathscript node using LabVIEW 7.1 and I cannot seem to make it work.
For example, consider that my mathscript node contains:
clear all;
close all;
x = linspace(1,100,5);
y = mltp(x);
where the labview vi is saved in the same folder as the mathlab script mltp.m that is given by:
function out1 = mltp(in1)
out1 = 5*in1;
Creating an array output of the mathscript node for y yields an empty array.
How can I use User-Defined functions in a mathscript node using LabVIEW 7.1?

Hello,
LabVIEW 8.2 did not yet have the MathScript page in Tools >> Options. In this version, you need to set the search path through the MathScript Window. Launch the window from Tools >> MathScript Window. Then go to File >> MathScript Preferences. It sounds like you have done this.
A first guess is that your .m file calls some unsupported functions or uses unsupported syntax. If that were the case, you could put the script in the Script Editor of the MathScript Window and select the "Save and Compile Script" menu item. This will return any errors from compiling the script. However, you said you simplified the problem to a single multiplication. Since this still does not work, I need more information. What are all the directories listed for the path in the MathScript Preferences dialog from the MathScript window? What is the working directory? Where is your .m file located on disk? Can you attach your .m file or paste the contents in your message?
Grant M.
Staff Software Engineer | LabVIEW Math & Signal Processing | National Instruments

Error 1097 after calling dll function which allocates memory inside

Hello!
When a call one my functions in my dll from LabView, i get an error 1097. My function takes a few arguments and then allocates some memory for measurement.
It's not returning any pointers to that memory area, it is just allocates that memory for itself. I don't know what could be the problem, probably i am missing something.
Could you help please?
Best regards,
Tamas
Solved!
Go to Solution.

Are you sure that the allocate function is the problem?
Error 1097 simply means something inside the external code wrote into memory locations that it was not meant to write. That is usually because of output buffer parameters that are not allocated (large enough) in LabVIEW when passed to the external code fucntion, so the function assuming it received a buffer of a certain size happily writes into that buffer but overwriting other information it should not have.
But that is by far not the only possibility to cause this error. A simple bug in the external code can cause the same problem when a pointer goes astray or such. The fact that you used that library elsewhere already without seeing any problem is unfortunately no guarantee that the function is not buggy. The LabVIEW exeception handling around the Call Library Node has gotten rather picky and can detect violations that do not have to cause visible problems at all. But the violations it detects are real violations so just silencing them is not a good idea, as they could cause all kinds of problems including overwriting vital data structures in your program that either cause a crash later on or simply wrong results in other parts of your program. Especially the last one is a total bummer to debug.
Without seeing much more of your code it is basically impossible to point out where the problem could lie. The particular Allocate function doesn't look like there is much that could be done wrong, but I would assume that you call several other functions too somewhere, which could cause the problem. If you can absolutely positively say that you never ever call any library function with a to short (or unallocated) buffer parameter, then you will have to take it up with the manufacturer of your lib, as it would seem very likely that there is some problem in there.
Also you pass a handle to the library function but your Allocate function does not have this as a parameter! Where does this handle come from? Are you sure you have allocated and prepared it properly before calling this function? A handle is quite often a pointer, although usually a so called opaque pointer meaning the user of the library does not and should not know anything about the structure this pointer points to. It is only known internal to the library.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Calling GetRawInputDeviceList function in LabVIEW

Hi,
I want to call GetRawInputeviceList function in the User32.dll using LabVIEW, but I am having difficulty in understandign the function prototype. To be specific, I am not clear what LabVIEW data types to be created for the arguments in the function. I went through this link http://msdn.microsoft.com/en-us/library/windows/desktop/ms645598(v=vs.85).aspx to understand the function prototype, but it is confusing.
Thanks

I created a LabVIEW Example based off of the example on the MSDN.
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C++:
The following sample code shows a typical call to GetRawInputDeviceList:
UINT nDevices;
PRAWINPUTDEVICELIST pRawInputDeviceList;
if (GetRawInputDeviceList(NULL, &nDevices, sizeof(RAWINPUTDEVICELIST)) != 0) { Error();}
if ((pRawInputDeviceList = malloc(sizeof(RAWINPUTDEVICELIST) * nDevices)) == NULL) {Error();}
if (GetRawInputDeviceList(pRawInputDeviceList, &nDevices, sizeof(RAWINPUTDEVICELIST)) == (<dtype rid="UINT"/>)-1) {Error();}
// do the job...
// after the job, free the RAWINPUTDEVICELIST
free(pRawInputDeviceList);
LabVIEW:
In case the snippet doesn't work, I also attached the VI.
*Note: It should also be noted that my error checking is very minimal. I check for the "-1" output on the first call to the function, but I really should use the Kernel32.dll to call GetLastError() as necessary. This is obviously a simplistic example.
EDIT:
If you have any specific questions about the code or function prototyping, feel free to ask. I'll be honest, this example took me a long while to replicate. Getting the structure to pass correctly took some trial-and-error
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If someone helped you out, please select their post as the solution and/or give them Kudos!
Attachments:
GetRawInputDeviceList.vi ‏11 KB

Can i call winmain function in labview

hello everyone,
Well i have written a C++ code that uses the winmain function (windows function). i want to convert this code into dll and call that dll into labview.
Is it possible to call winmain function as one of the functions in labview. Please let me know as soon as possible.
Thank you.
Royal tiger......

You didn't say what development environment you're using, so I'm assuming Visual Studio. It sounds like you created a Win32 app (as opposed to an MFC app). This has a "WinMain" function. The prototype for WinMain is geared towards it being called by the OS when you run the executable. You could just add the __declspec(export) directive in front of the return type, but you also need to change some build functions in Visual Studio to get a DLL. You probably also don't need all the arguments that WinMain uses. You're probably better off by starting with a new DLL project in order to get the framework for a DLL, and then copy and past the function code. That's what I would do.
I would also strongly suggest that you crack open the "Using External Code in LabVIEW" manual that gets installed when you installed LabVIEW. It's in the "manuals" directory, filename of "lvexcode.pdf".

Calling DLL function using LabVIEW 7.1?

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