How do I determine what compiler was used to create a DLL?
I have a DLL - is it possible to find out how the DLL was created (.NET/C++/Labview etc). I don't have the source of the DLL file. I tried checking with decompilers also, but it does not provide me any information of how the DLL was created.
There are a number of tools for performing this sort of analysis. Have a look here for a summary of some popular options (namely PEiD, Exeinfo PE, and Language 2000).
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How can one programmatically determine which type libraries (GUID and version) a given native, VB6-generated DLL/OCX depends on?
For background: The VB6 IDE chokes when opening a project where one of the referenced type libraries can't load one of its dependencies, but it's not so helpful as to say which dependency can't be met--or even which reference has the dependency that can't be met. This is a common occurrence out my company, so I'm trying to supplement the VB6 IDE's poor troubleshooting information.
Relevant details/attempts:
I do have the VB source code. That tells me the GUIDs and versions as of a particular revision in the repo, but when analyzing a DLL/OCX/TLB file I don't know which version of the repo (if any--could be from a branch or might never have been committed to a branch) a given DLL/OCX corresponds to.
I've tried using tlbinf32.dll, but it doesn't appear to be able to list imports.
I don't know much about PE, but I popped open one of the DLLs in a PE viewer and it only shows MSVBVM60.dll in the imports section. This appears to be a special quirk of VB6-produced type libraries: they link only to MSVBVM60 but have some sort of delay-loading mechanism for the rest of the dependencies.
Even most of the existing tools I've tried don't give the information--e.g., depends.exe only finds MSVBVM60.dll.
However: OLEView, a utility that used to ship with Visual Studio, somehow produces an IDL file, which includes the importlib directives. Given that VB doesn't use IDL files, it's clearly generating the information somehow. So it's possible--I just have no idea how.
Really, if OLEView didn't do it I'd have given it up by now as impossible. Any thoughts on how to accomplish this?
It turns out that I was conflating basic DLL functionality and COM. (Not all DLLs are COM DLLs.)
For basic DLLs, the Portable Executable format includes a section describing its imports. The Optional Header's directory 1 is about the DLL's imports. Its structure is given by IMAGE_IMPORT_DESCRIPTOR. This is a starting point for learning about that.
COM DLLs don't seem to have an equivalent as such, but you can discover which other COM components its public interface needs: for each exposed interface, list out the types of their properties and their method arguments, and then use the Registry to look up where those types come from. tlbinf32.dll provides some of the basic functionality for listing members, etc. Here's and intro to that.
I'm trying to interact with a .dll which will allow me to receive information from a variety of devices (Eye Gaze to be specific). The .dll is called ETUDriver and can be found at http://www.sis.uta.fi/~csolsp/projects.php however it does not come with an accompanying .h file.
I am struggling to actually load, interact and invoke functions from the .dll. A manual is supplied but it is of no help whatsoever with regards to actually setting up the code to start it off. There are three accompanying example apps (with source code) but only two of these work and one of which is in C# so is not helpful. The one that works however loads up the .dll via MFC and this is not a viable option with my code (which is intended to be used with many other projects and as such can't enforce MFC or any other libraries that are not as standard to projects).
Essentially, within the .dll is a series of classes which I need to create within my code and invoke the relevant functions of that class.
I've tried to use HRESULT hr = CoInitialize(NULL);
hr = CoCreateInstance(__uuidof(ETUDSink), NULL, CLSCTX_INPROC, __uuidof(IETUDSink), (LPVOID*)&pETUDSink);
if(pETUDSink)
{
pETUDSink->Start();
} however it always returns an error saying that the class is not registered. I can't use MFC to call the relevant .rgs file and am completely stuck on how to get this to work otherwise.
Is there a given format to doing this that I am unaware of and has anyone had experience in using the ETUDriver (or is able to get it working in C++ without use of MFC)?
Thank you for any help you can provide on this subject :)
I am not familiar with the specific DLL in question, but it sounds like you did not register the DLL on the target machine. You can do this by running regsvr32.exe or by calling the DLL's exported DllRegisterServer function or by using side-by-side assemblies. You need to do register the DLL on each machine that needs to leverage the COM functionality within it, so when you distribute your application, make sure that your installer registers the DLL if you go the regsvr32.exe route.
You can use the #import directive in Microsoft Visual C++ to load the information contained within the DLL without using a header file or rewriting it yourself based on documentation.
I'm trying to create an D application which uses a (third party) COM .dll so I can scrape a text box of another application so I can sound an error when a certain string shows up.
However the third party doesn't provide .lib, .def or .h files that go with the dll (atleast with the free trial version). I can create the .lib file with the implib tool but I don't see any of the library's functions in the created .lib.
Their (visual c++) samples use the #import directive to link it in however that is of no use for me ...
On a side note how can I get the proper interfaces (in a .di with boilerplate that does the linking) of the dll automatically? I ask so the correctness of the linkage doesn't depend on my (likely to be incorrect) translation of the functions. They do have a webpage which gives all functions but the object model is a bit chaotic to say the least.
From what I know, COM libraries only expose a few functions, required to (un)register the library and to create objects.
You can however view the interfaces and functions in a COM .dll using the OLE/COM Object Viewer. It seems it might be able to output header files (.h). Afterwards, maybe you could use htod as a starting point to converting everything to D interfaces.
The DMD distribution seems to include a .COM sample (chello.d, dclient.d, dserver.d), and at first glance it doesn't look like it would require any LIBs explicitly.
Unfortunately, I've never actually used COM in D, so I can't advise any further. I hope this helps in some way.
While I have yet to actually do COM work myself, I am trying to revive Juno over on Github/he-the-great. Part of the project is tlbimpd which is what will output a D file from a DLL.
I've tested the examples and successfully run tlbimpd. Please do try things out for your use and submit any issues.
What is the meaning of building a dll as export library ? I just googled it.I found its a dynamic link library.Can anyone please explain what actually dll is ? and why do we need to add these statement in the .dll file
extern "c" _declspec(dllexport)
I studied the static and shared libraries but Im not sure why do we go for dll files.I learnt .dll is used for the run time. But can you help me and give me more information.Thank you in advance
I may have been a bit harsh in my comments. I am not an authority on dlls, but I have a bit of working knowledge of them, so I will try to give a short explanation.
The difference between static and shared libraries should be easy to find in a web search, but basically the code in a static library gets included into the final executable, so after the linking stage, the actual library file is not needed anymore to run the program; on the other hand, code in a shared library doesn't get included in the main program - the two parts remain separate, so the shared library (called dll on windows) will be needed every time the program is run.
"Building a dll as export library" is a bit of a confusing term. I had not heard of it before, and during a short search could only find it on a cygwin page, which you might have read, considering your initial tags. A dll can export some or all of its functions and data. Exporting means that they are available for other programs and dlls to use. Which names get exported can be controlled in various ways. One of those is inserting _declspec(dllexport) in the declaration of the function. Another way is by using a definition file with an exports section.
When creating a dll, an import library can be created. This is a file that can then be used when building an executable that uses the dll, during the linking stage, to let it know which names are exported from the dll, so the program knows how to resolve references to those functions; in other words: how to import them. (This is not always necessary. Many linkers allow you to directly link against the dll itself, thereby removing the need for an import library.)
I realize it can be confusing, but try to find a tutorial and some small examples to see how it works, and play with it a bit.
I thought it would be Common Intermediate Language, but in notepad it does not look like that at all. Does it just look uglier in reality than in tutorials? Or is it some bytecode form that is further compiled from CIL?
It's CIL is the name of the binary format, not of the "assembler" you're thinking of.
Can you possibly imagine that .NET assemblies would be text files?
A .NET executable is a binary file that has a PE header (same as a native executable, but with slightly different values). The PE header tells the OS to load the CLR, which in turn loads the assembly.
The content beyond the header is a binary representation of the CIL code, plus some metadata and other stuff. The text you see in tutorials is the text representation of CIL, in much the same way that the assembly language code you see in a tutorial about assembly language programming is just the text representation of the binary machine code.
See http://www.yetanotherchris.me/home/2010/7/12/inside-net-assemblies-part-1.html (among many others) for more information.
A .Net executable is usually not written, it is compiled from another language such as C#, F# or VB.Net.
The contents of a .Net executable can be viewed with the ILDASM tool.
The contents are first a manifest which is used for reflection, signatures or other meta-code purposes.
Secondly there are the MSIL instructions themselves. These are in a kind of bytecode format, but ILDASM will show you what the instructions are.
And there are sometimes resources such as imagery, sounds or other content packed into the executable.
The executable is just-in-time compiled to native code either during installation (I think this is uncommon), or as a precursor to execution. The resulting native code can be stored for reuse. (This is what I was told during PDC 2001, might be "out of date".)