Generate header file from dll

By copying the output of DUMPBIN to the clipboard, pasting it to a text file, and modifying it appropriately according to the format of a def file, we can arrive at the following def file:.

A header file to be included at the DLL's caller side should contain the prototype of the exported functions.

In our example, the core part of the header DllSample. The inclusion of extern "C" is to instruct the compiler to use C-style name mangling, to allow programs written in C to use our lib.

The target files of the MakeLib project are not MakeLib. To avoid name collision, the original DLL, i. The DllUtil. The inclusion of project DynCall in our workspace is because DynCall and MakeLib share a large portion of source code, and DynCall is useful in its own right.

The data part of DynCall and MakeLib are very similar, but they also have important differences. In both sources, there are many pointers to the imported functions, but in DynCall they must be declared as global, whereas in MakeLib they must be defined as static, since they need not be externally linked.

Roughly, the core source snippet of MakeLib. At this point, the reader may wonder why I used so many "weird" macros. Macros are not really useful if you only have a handful of functions, but a commercial DLL may well export hundreds of functions, and in such cases using a suitably designed set of macros can save us a lot of typing work.

I myself have a direct experience on this. The code for this functionality is the same as in ImportDllSample. Now let us look at the implementation of exported wrapper functions. But how do we achieve this? Please see the following code snippet excerpted from MakeLib. There is a detailed explanation of it in MSDN. Now we launch UseLib. So if you wish to check that DllSample. We can now see that the so-created DllSample.

To sum up, the above-described procedure for import library creation has two merits:. Sign in Email. Forgot your password? Search within: Articles Quick Answers Messages. Stats Yiping Cheng Rate me:. Please Sign up or sign in to vote. A tutorial to guide you through the process of creating a lib from a third-party DLL.

In general, it won't be possible at least not with ELF files on Linux. Because type and signature information is not kept e. However, C compilers don't do that.

For example, you can't even reliably know how many arguments a given function notably a C one is expecting, and even more their type. And some functions don't have externally visible names e. Read more about ABI s e. However, if the code has been compiled using -g with debug information in DWARF , it could be possible.

Read also about the strip command. And if you have additional a priori information for example, knowing that the given library is distributed by Debian it probably should be possible.

Some projects perhaps FOSSology , but I could be wrong simply guessed free software libraries by comparing their constant literal strings against a previously built database of them. BTW, what you are looking at is more or less called a decompiler and the process would be decompilation.

Read also about obfuscation. With a lot of efforts and resources e. No, this is not generally possible. Libraries are self-describing in that they list all available symbols functions and variables with external linkage. But they do not contain sufficient information about the types. This is not just a matter of providing the names of all types, e. To properly satisfy the calling convention we need to know the layout and specifically the alignment of that type. So we would need to embed the complete type information that would also be provided by a header.

Of course incomplete types can be elided. The header files can be seen as an interface description language that provide all this information. In this set of tasks, you create a project for your DLL, add code, and build it. The instructions vary slightly depending on which version of Visual Studio you're using. Make sure you have the correct version selected in the control in the upper left of this page. In the Configure your new project page, enter MathLibrary in the Project name box to specify a name for the project.

Leave the default Location and Solution name values. Set Solution to Create new solution. Uncheck Place solution and project in the same directory if it's checked. When the solution is created, you can see the generated project and source files in the Solution Explorer window in Visual Studio.

Enter MathLibrary in the Name box to specify a name for the project. Check Create directory for solution if it's unchecked. Enter MathLibrary in the Name edit box to specify a name for the project. Choose the Next button. When the wizard completes the solution, you can see the generated project and source files in the Solution Explorer window in Visual Studio. Right now, this DLL doesn't do very much. Next, you'll create a header file to declare the functions your DLL exports, and then add the function definitions to the DLL to make it more useful.

In the center pane, select Header File. Specify MathLibrary. Choose the Add button to generate a blank header file, which is displayed in a new editor window. This header file declares some functions to produce a generalized Fibonacci sequence, given two initial values.

Notice the preprocessor statements at the top of the file. This modifier tells the compiler and linker to export a function or variable from the DLL for use by other applications. This modifier optimizes the import of the function or variable in an application. For more information, see dllexport, dllimport. Create a new. In the editor window, select the tab for MathLibrary. If not, in Solution Explorer , double-click MathLibrary.

To verify that everything works so far, compile the dynamic link library. The DLL and related compiler output are placed in a folder called Debug directly below the solution folder. If you create a Release build, the output is placed in a folder called Release. The output should look something like this:. Next, you'll create a client app that uses the functions exported by the DLL.

When you create a DLL, think about how client apps may use it. To call the functions or access the data exported by a DLL, client source code must have the declarations available at compile time. At link time, the linker requires information to resolve the function calls or data accesses. A DLL supplies this information in an import library , a file that contains information about how to find the functions and data, instead of the actual code.

And at run time, the DLL must be available to the client, in a location that the operating system can find. Whether it's your own or from a third-party, your client app project needs several pieces of information to use a DLL. One solution is to copy all of these files into your client project.

For third-party DLLs that are unlikely to change while your client is in development, this method may be the best way to use them. However, when you also build the DLL, it's better to avoid duplication. If you make a local copy of DLL files that are under development, you may accidentally change a header file in one copy but not the other, or use an out-of-date library.

Connect and share knowledge within a single location that is structured and easy to search. I've been testing things with multiple project setups where a console application accesses functions from several DLLs. I thought about how to include the DLLs' headers in the console application. My current implementation is as follows but it's being a headache to manage and even sometimes runs into errors:. It worked out fine until I started overloading operators. I believe the grief is caused by the pre-compiled header somehow, here's and example of my current usage of stdafx:.

With this I sometimes get some irrelevant random compiler errors that I can hackfix by excluding the header from the "master header" and including the troublemaker separately in the console app. These definitions should not be in stdafx. This is incorrect, every Dll must have unique preprocessor definition. As already mentioned in the comments, using namespace can be used only in source files. Stack Overflow for Teams — Collaborate and share knowledge with a private group.