Use aspects and variables of the imported DLL in a console application.

Like a fully statically linked library, a DLL exports factors, functions, and resources by name. The client application imports names to use personal variables, functions, and resources. Unlike a statically linked library, Windows bundles your app’s imports and exports into a complete DLL at load or during use, rather than linking them in at the same time. Windows requires additional information, which is not necessarily part of the standard C ++ compilation, in order to establish these connections. The MSVC compiler implements some Microsoft-specific extensions for C ++, if you’d like to provide this additional information. We explain how we make extensions.

This walkthrough creates a number of Visual Studio solutions. that you are building all the DLLs and Patron application. DLL uses C according to convention. It can be called by applicationswritten in other programming languages ​​if the platform, calling conventions, and backreference conventions are the same. Client, the application uses a default link where Windows optionally links the application to the DLL at boot time. When you link this, your application can call functions provided by the DLL, just like functions in a statically managed library.

This does not cover some basic situations. The code does not show the use of similar C ++ libraries by other programming languages. It does not show how to create the latest resource-only DLL or how to use an explicit link as opposed to load time. Be sure MSVC and Visual Studio can do almost all of these things. Links

For more information on DLLs, see Creating C / C ++ DLLs in Visual Studio . For more information on implicit backreferences and explicit referencing, see Determining which configuration method to use . For more information on rebuilding C + DLLs + for use in various programming programs For creation using the C binding conventions, see Exporting C ++ Functions for Use in Executable C Languages ​​. For information on creating DLLs for use with .NET languages, see DLL Calling Functions for Visual Basic Applications .

Requirements

• The mobile computing device is running Microsoft Windows 7 or earlier. We recommend Windows 10 for the best development experience.

• Understand the basics of using the Visual Studio IDE. If you’ve used Windows desktop apps before, you can definitely keep up. For an overview, see Overview of Visual Studio IDE Features .

• Achieve sufficient knowledge of our C ++ language to participate. Don’t worry too much, we’re not doing anything too complicated.

Create An Exact DLL Project

In this task, the client creates a project for your DLL, improves the code, and builds it. First, start with the Visual Studio IDE and sign in if necessary. Easily customizable instructions depending on The version of Visual Studio you are using. Be sure to include the correct version selected in the command in the upper left corner of the page. Now

The fix does not make this DLL too extreme. Next, you’ll create a header file to help you declare the functions that your DLL will export, and then add function definitions to that DLL to make it more useful.

1. To formulate a file header for your functions, choose Project> Add New Item from the menu bar.

2. In the Add New Item dialog box, select Visual C ++ in the left pane. In the middle, select Header (file.h). Enter MathLibrary.h as the current header file name.

3. Usually click the Add button to generate a white header file that will be displayed in the next editor window.

4. Replace the content of the database header with this code:

     // MathLibrary.h - contains math function declarations#pragma once#ifdef MATHLIBRARY_EXPORTS#define MATHLIBRARY_API __declspec (dllexport)#another#define MATHLIBRARY_API __declspec (dllimport)#end if// Repetition of the Fibonacci ratio describes the sequence F// where F (n) {n = 0, a. will// {d = 1, b// {n> step 1, F (n-2) + F (n-1)// for some important initial values ​​a and b.// .if .zone. Initialized .F (0). = .1, .F (1). Means .1,// then this relationship generates the famous Fibonacci shape.//. Sequence: .1, .1, .2, .3 ,. Row, .8, .13, .21, .34, ....// Initialize almost any sequence of Fibonacci ratios// so F (0) implies a, F (1) = b.// The function must be called before any other function.extern "C" MATHLIBRARY_API void fibonacci_init (    unsigned constant long long a, unsigned constant extended long, producing b);// next value here in sequence.// Returns true on success, so the current value and invalid index are updated;// Overflow, leave current value and database unchanged.extern "C" MATHLIBRARY_API bool fibonacci_next ();// get the last value of the sequence "C"extern MATHLIBRARY_API unsigned long long fibonacci_current ();// NSGet the position, including the current value in the sequence.extern "C" MATHLIBRARY_API unsigned fibonacci_index (); 

This header file declares some functions to create a generalized Fibonacci chain with two given initial values. A phone call asking for help fibonacci_init (1, 1) generates the familiar magnitude of the Fibonacci sequence.

Pay attention to the preprocessor instructions at the top of the file. New web project design for DLL project adds PROJECTNAME_EXPORTS with specific macro preprocessor. For example, the above Visual Studio sets MATHLIBRARY_EXPORTS when you build your MathLibrary DLL project.

If the MATHLIBRARY_EXPORTS macro is defined, the MATHLIBRARY_API macro __declspec (dllexport) leaves a modifier for function declarations. This modifier tells the compiler and Marketplace to export a function or variable from a specific DLL for use by other applications. If MATHLIBRARY_EXPORTS is not defined, for example, if all header files are contained in the same application, MATHLIBRARY_API applies the __declspe modifier to the declarationsc (dllimport) . This modifier optimizes the movement of functions or variables when used correctly. See dllexport, dllimport for more information.

To Create A DLL Implementation

To make sure everything works, compile a dedicated dynamic link library. Compile to select Build> Build Solution from the pub menu. The DLL and its associated compiler output are actually placed in a folder named Directly debug in the solution folder. When you go to release a release, the result is placed in a folder called Release. The end result should look like this:

Congratulations, you have created the DLL with Visual Studio! Next, you’ll make sure to create a client application that will use each of our DLL exported functions. A

Create A Client Application Using The DLL

When preparing a DLL, consider how client programs might use it. Get or access works

Owen Coppleson