Rolf Kalbermatter

QUOTE(wbiker @ Sep 7 2007, 02:28 AM) By clicking the stop button on the toolbar you are not stopping the VI but really aborting it. If the program execution was at that point in an external code part you can end up with a locking situation since the external code may wait one some event message processing which will not happen anymore since the whol application was basically taken down brutally. Most NI drivers especially in newer LabVIEW versions are writting in such a way that they get informed by LabVIEW about aborts so that they can abort any waiting, but third party drivers usually don't have that, also because the means to be informed by LabVIEW about aborts are not really documented. But even NI drivers can still sometimes get stuck in such a way. The toolbar stop button is really just a last measure to abort a program or for quick and dirty testing but should not be used as normal way of starting and especially stopping a LabVIEW program. The LabVIEW program should have some sort of event processing with an explicit quit button in which case the event processing loop (and any other parallel loop that might be running) gets properly terminated after which you can clean up any DAQ, Instrument, IO-Bus, etc operation properly by closing those resources and once the last item on the diagram has executed the program stops too, but this time cleanly. Rolf Kalbermatter

QUOTE(Karissap @ Aug 31 2007, 01:38 AM) Only if you are quite good at C and integrating that through a DLL into LabVIEW. The System Tray API in Windows uses callbacks and integrating that with LabVIEW is not trivial. ActiveX should be easier but I don't think there is a standard Windows ActiveX control that does System Tray. QUOTE(MikaelH @ Aug 30 2007, 08:17 PM) You can then create the "Icon tray" object set its properties/icons and then when a user interacts with the system tray icon the .net part fires call backs to LabVIEW. The .Net System tray API seems to have a problem somehow. I've seen several applications using that and they all seem to not remove the icon from the system tray when the application closes. Apparently there is no way to properly cause such an icon to disappear, especially when the application closed unexpectedly. Rolf Kalbermatter

QUOTE(LV Punk @ Aug 29 2007, 06:26 AM) Since you plan on throwing away any but the last data anyhow a notifier may be better than a queue in this particular situation. Rolf Kalbermatter

QUOTE(jlokanis @ Aug 29 2007, 12:43 PM) Well if you have a LabVIEW version before 8.0 somewhere you can copy the stuff from there. There was no lvlib before 8.0. Alternatingly I wrote long ago a library that works similar to the NI Eval Formula function but is implemented a bit differently dividing the evaluation cleanly into a parser that creates UPN stack intermediate code and an evaluater that operates on that intermediate code. I needed that for speedy calculations where user entered formules would be needed but they didn't change all the time, so parsing the formula once and then evaluating it over and over again had some serious perfomance advantages. The parsing is not trivial but a lot more streamlined than the NI code and the entire thing is also faster. It hasn't been updated for several years but worked fine for what I needed it. LabVIEW 5.0 ExprEval.zip Rolf Kalbermatter

QUOTE(adriaanrijllart @ Aug 29 2007, 11:41 AM) Hi also. I do remember having met you and yes it is quite some time. In the meantime I'm living for already 11 years in the Netherlands ;-) Greetings Rolf Kalbermatter

QUOTE(adriaanrijllart @ Aug 14 2007, 12:48 PM) As far as I know it doesn't exist and the chance that it will is small. HTTPS requires a serious amount of encryption technology and writing encryption code in LabVIEW is not the most efficient thing to do. But the most critical aspect is the fact that writing encription routines is a tricky business that not many people know about, and unless you are an absolute pro in that area trying to do it is likely to not work or even worse pose serious security risks when using that code. Most people using LabVIEW are simply not professional encryption/security specialists. Using existing C code has the problem that the actual HTTPS encryption actually is put at the lowest level just above the network protocol. So there would be only two possible ways: 1) inject an HTTPS encryption layer into the TCP/IP stack so that LabVIEW does not deal with that encryption at all. This is very difficult to do and would require some state aware encryption layer in a low point of the entire protocol stack that depends on the protocol state of a higher layer. Not really a good idea. Better idea in that context would be to use something like putty and just create a secure tunnel through which the normal HTTP protocol goes. This would require that you can influence the server side too, as you would have to setup an according VPN or similar connection. 2) using the C libraries implement the HTTPS protocol on top of the LabVIEW TCP/IP primitives. Technically the right way but so much work that I would not even consider doing it unless I can find a government sponsored project that would pay for that :-). In short forget it as it would be quite expensive already! Well cheaper and more secure than trying to implement the HTTPS security infrastructure entirely in LabVIEW, but still not practical. Rolf Kalbermatter

QUOTE(paracha3 @ Aug 23 2007, 10:05 PM) Tomi has been right with all his recommendations. No need to use a Visual Source Safe compatible interface, unless you want to invoke the source code control actions directly from within LabVIEW. In my experience using SVN with Tortoise SVN however works actually better. Of course you need some discipline but that is in the nature of source code control anyhow. One extra note, if you really want to access your source code control system directly from within LabVIEW you do need a Visual Source Safe compatible interface plugin. LabVIEW simply interfaces to that API and accepts any compatible source code provider that has been registered in the system. If you can't find a commercial interface for your SCC (but if it is popular at all in any means you probably can) you would have to write it yourself. From what I understand it is not to difficult to do that but the API is considered proprietary information by MS and you only get it by signing an NDA, or at least that was the situation last time I checked into this. Rolf Kalbermatter

QUOTE(RiverdaleVIEW @ Aug 21 2007, 07:58 AM) Well a 2D array in C is VERY ambigious. Without knowing more exactly what the programmer did intend and use you can generally not say for sure how it is implemented just from the prototype. You can implement a 2D array as one single chunk of memory with allo rows (or for the kick colomns) put after each other). This is the way LabVIEW handles 2D arrays. It is as far as the memory layout is concerned just a single 1 dimensional array with all rows streamed (serialized). This is pretty efficient and cool with one single drawback. Since you only know the number of rows and columns for such an array each row will have to have the same length, resulting really into an array of rows * columns elements. Another possibility is to create an array of pointers to 1D arrays. This results in the int **a syntax and is a bigger load for the memory manager. This array can NOT be created nor passed by LabVIEW directly to a DLL nor exported from a LabVIEW DLL. One of the reasons is that there is no way for LabVIEW (and any C compiler actually) to know if this is just a double referenced pointer to a single variable or if it is an array of pointers. int *a[] would be a bit clearer in that sense but traditionally C compilers make no difference between int *a[] and int **a. So if you have an int *a[] or int **a parameter anywhere in your DLL functions, you are going to have to create a C wrapper function in this or a saparate DLL to translate between LabVIEW and your DLL. Rolf Kalbermatter

QUOTE(Sarfaraz @ Aug 10 2007, 05:52 AM) This message is normal. LabVIEW has been compiled without debugging information for several reasons. One of them is the size it would take, another one the fact that debugging information can expose sensitive information in the executable that makes dissasembling it very easy. You should be able to ignore that message and just continue. I have no experience with Visual C 2005 but in Visual C 6 it is just like that. As long as your DLL was compiled with debug information the Visual C debugger should show you source code debugging for your DLL. It could be that you get prompted for the project file at first launch so Visual C can locate the source files. Of course if you start to single step from your code into LabVIEW code you will only see assembly there. Rolf Kalbermatter

QUOTE(Aristos Queue @ Jul 23 2007, 05:29 PM) This sentiment! Is that official NI policy now? Maybe it has come the time to consider for me if LabVIEW is still the tool I love to work with. Rolf Kalbermatter

QUOTE(Yuri33 @ Jul 22 2007, 10:36 PM) It's not undocumented. It is all (except the Library:LabVIEW trick in the Call Library Node) there in the External Code Reference Manual. Rolf Kalbermatter QUOTE(Aristos Queue @ Jul 22 2007, 11:38 PM) No, and using such callbacks is a trick we go to great lengths to prevent folks from doing. Yea, I figured some of the password protected VIs might use this and similar tricks ;-) But someone at NI must have forgotten that. There is or maybe used to be a code example on the Developer Exchange Site exactly with the MoveBlock function. So you hardly can call the Library:LabVIEW trick in the Call Library Node to be a well kept secret anymore. Rolf Kalbermatter

QUOTE(eaolson @ Jul 19 2007, 09:31 AM) I haven't thinkered with projects and such in VI server yet but this is just some of the basic understanding I have about LabVIEW VI server. The targets in a project should be more or less just like application references. And the way to open a VI in the context of an application reference is to pass that application reference to the Open VI Reference function. Have you tried to connect one of those target references to the Open VI Reference or maybe search for a property in the target reference that might return a real application reference? Rolf Kalbermatter

QUOTE(Aristos Queue @ Jul 20 2007, 02:42 PM) The way I do this is by calling the LabVIEW internal memory manager function MoveBlock through a Call Library Node. If you set the source parameter to be an uInt32 by value and the target parameter to be an uInt(x) by reference, and then also adjust the size parameter accordingly you get what is required. To call MoveBlock in LabVIEW you have to configure the Call Library Node as follows: Library Name: LabVIEW Calling Convention: Standard C Function Name: MoveBlock return value: void 1. param: source, uInt32 as Value 2. param: target, uIntxx as Pointer 3. param: size, int32 (number of bytes to copy) Advantage is that you do not need any Toolkits or plattform specific external libraries. Rolf Kalbermatter

QUOTE(Dirk J. @ Jul 20 2007, 09:03 AM) I think this has a memory leak. The IDList returned by SHBrowseForFolder is a memory buffer that should be freed with the (originally undocumented) ILFree function in shell32.dll. And for OSes before XP or 2000 this function was not exported by name, but only as ordinal number 155. A little known feature of the Call Library Node is that you can also reference functions that are exported by ordinal by entering the ordinal number as function name. LabVIEW seems to attempt to convert function names that only consist of numbers into an ordinal and try to load the function as such. Rolf Kalbermatter

QUOTE(Gary Rubin @ Jul 18 2007, 04:11 PM) Yes, the rules if LabVIEW does a data copy are mostly tied to the functions the wire runs to and especially if a wire has branching built in. And here multithreading might get in the place sometimes. When a wire branches, LabVIEW tries to execute functions that only read the data but don't reuse them further or create a complete copy anyhow before functions that could reuse the buffer. In that context subVIs are always considered as a potential consumer of a buffer. And now if you have multithreading in place LabVIEW might get in a difficult sitution: Serialize the code to execute non consuming nodes first or allow simultanous execution that requires a data copy in any case. I would opt myself for the first case as it should probably in most but the simplest cases where only skalars are involved be the more efficient solution. Rolf Kalbermatter

QUOTE(tcplomp @ Jul 18 2007, 04:34 AM) The http://www.vartortech.com/visecurity/cryptg.html' target="_blank">CryptoG Toolkit contains amongst many encryption and hash algorithmes a Random Number Generator and based on that a VI to create GUIDs. All these functions are fully native G code and tehrefore completely plattform independant. It's cost is nothing that should prevent you using it and I can really recommend it. Rolf Kalbermatter

QUOTE(Neville D @ Jul 13 2007, 10:55 AM) The TCP functions will return errors if no network card or at least a TCP/IP adapter (modem, broadband or whatever) is present in the system to which the TCP/IP socket layer can bind to or if those adapters are all disabled. Though I wonder if there still exist PCs without a network interface. Rolf Kalbermatter

QUOTE(Karissap @ Jul 12 2007, 11:39 PM) And it is likely to not work as desired in an executable. Rolf Kalbermatter

QUOTE(Tomi Maila @ Jul 11 2007, 02:11 PM) While in theory your conerns could be right they don't have to be for two reasons. 1) As long as you do nothing with a wire (and data dependency can ensure a variable stays put in memory until after a certain point) LabVIEW does not deallocate or move it. In fact all diagram data (except paths) are stored as DS (Data Storage) memory contrary to AZ (Application Zone) memory. The distinctions (although I believe in practice this makes no difference on most modern platforms anymore as the memory virtualization of modern 32bit CPUs completely hides the physical memory management of the CPU from all applications) is that AZ memory handles can be locked but don't need to be while DS memory handles always are locked. A locked handle means that the memory manager will never move around your memory block while you do other things in LabVIEW, unless you explicitedly use memory manager functions to deallocate or resize such a handle. Pointers are by their nature non relocatable unless explicitedly reallocated. 2) The memory manager has some very powerful functions that can directly move between pointers and handles and that ensure that the operation is properly protected in the context of the LabVIEW execution system. But even without this, as long as you make sure that no other LabVIEW functions can concurrently operate on a handle whose pointer you treat with your direct DLL magic functions, you can be sure to be safe. And by the way this is why LabVIEW has to and does make data copies on branching wires when more than one function can possibly modify that data. Rolf Kalbermatter

QUOTE(polyplay @ Jul 9 2007, 04:11 AM) If your actual C code header file is really as you show in your text file you might have a serious problem here. typedef struct { unsigned int LINMode; int baud rate; < this is definitely not valid C syntax. unsigned int LINVersion; unsigned int reserved; } XLlinStatPar; XLstatus xlLinSetChannelParams (XLportHandle portHandle, XLaccess accessMask, XLlinStatPar statPar); What LabVIEW will assume for structure parameters is: XLstatus xlLinSetChannelParams (XLportHandle portHandle, XLaccess accessMask, XLlinStatPar *statPar); passing the structure by pointer. I'm not aware that this can be done otherwise so maybe the C compiler will automatically make this parameter passed by pointer but that is beyond my C detail knowledge. Rolf Kalbermatter

QUOTE(Yuri33 @ Jul 8 2007, 11:46 PM) A less costly and also platform independant way is to use a Call Library Node to allocate memory areas by calling into LabVIEW itself. Setting the library name to LabVIEW you can call all the exported LabVIEW manager functions that are documented in the External Code Reference Manual and that includes the LabVIEW memory manager that can do all this. Make sure to use C calling convention as that is what LabVIEW exports its manager functions as, and obviously configure the rest of the Call Library Node according to the documentation for the function you want to call. Advantage is you don't need an (expensive) Toolkit installed and if you ever happen to have to move these functions to another LabVIEW platform this part will simply continue to work (the DLL part itself obviously not . Don't forget to deallocate the memory poiunters after use obviously as otherwise you create memory leaks. Rolf Kalbermatter

QUOTE(Yuri33 @ Jul 5 2007, 10:52 PM) IMAQ AVI file reference is not a proper LabVIEW refnum, but a private implementation to the IMAQ AVI library. So the Not A Refnum prmitive can't work there as it is strictly always not a valid LabVIEW refnum. What you can do is either try to typecast the refnum into an int32 and if it is not 0 then assume it is valid or probably even more safe use the IMAQ AVI Get Info function. If it returns no error then it is definitely a valid refnum. Of course the issue about why you would need to find out after the fact if it is a valid refnum does hint that you probably do not do proper error handling of the Create or Open function. Rolf Kalbermatter

QUOTE(robijn @ Jul 4 2007, 10:44 AM) I was pretty sure that LabVIEW terminated strings on return on the first NULL character already in LabVIEW 7 and I think even in LabVIEW 6. I did rely in 6.x several times on that, so not sure why you would see something else. If that is not desired you need to use byte arrays. Rolf Kalbermatter

QUOTE(PeterB @ Jul 4 2007, 07:50 AM) You don't! LabVIEW can NOT do anything with lib and obj files. That is for C compilers only and even then you have to have lib and obj files that are compatible for your C compiler, eg. meaning they should have been created by the C compiler you want to use them with too. You can't create a LabVIEW DLL and hope that LabVIEW will link to your lib file magically. A LabVIEW DLL is really a LabVIEW LLB with very small exported C wrappers around those VIs inside the LLB. There is no way you can influence the C wrapper generation made through the LabWindows CVI runtime engine to somehow include your lib file and even if you could it wouldn't help either, as the wrapper code generation does not know how to link to other lib files than what is necessary to wrap the VIs such that they can be called as a DLL export function. If this lib file is only an import library to the actual functionallity in a DLL then you could instead link to that DLL through the Call Library Node. Otherwise there will be no way around creating some C code to be put in a DLL and that can be called by LabVIEW that links with your lib file. In that case you need to create a DLL in Visual C, that you can call from LabVIEW and you want to include that lib file into that Visual C DLL project. I hope I didn't confuse more than help but it's simple! If the actual functionality of your lib file is not located in a DLL file for which you have documentation and the API interface, then you WILL have to create a C DLL first. Ok I reread the first post once more and I see that you want to create a DLL to be integrated in VisSim and that the DLL needs to link to vissim32.lib. This can't work without Visual C. In fact their statement that any environment that can create DLLs should work is mostly wrong. Besides Visual C there is only LabWindows CVI and proabably Borland C that can directly link with vissim32.lib. lib and obj files are binary files that can come in many flavors and Visual C will generate and require so called COFF format, while Borland will generate and prefer OMF format. LabWindows CVI used to support both formats for generation and linking but you needed to decide whith format you wanted during installation. LabVIEW can not generate obj files. What it can and does do is generating Visual C compatible import libraries for the LabVIEW generated DLLs. So what you can do if you need to generate Vissim callable DLLs that incorporate LabVIEW code is to generate the LabVIEW DLL and then generate another C DLL that also includes the lib file for vissim32.lib and your LabVIEW DLL import lib file. Rolf Kalbermatter

QUOTE(PeterB @ Jul 3 2007, 11:49 PM) Well if you create a DLL you always link with lib and/or obj files unless you never use any library functions, be it LabVIEW External Code functions, C runtime functions, or Windows API functions. But in Visual C you don't need to specify the C runtime library and Windows API import library specifically since most of them are added by default to a project and the Visual C linker picks from them whatever he needs. An obj file is the compiled form of a single .c or similar file and a lib file is just a collection of several obj files. EXEs and DLLs are the combination of all obj and lib files with some extra startup stub and possibly resources and other custom stuff put into. Basically you want to add your custom library file to your project somehow. You can do this by adding it explicitedly to the files that your project consists of, or in the project settings add the name of the library under Linker Settings and also provide a path to the directory where Visual C can find that library. Rolf Kalbermatter