An Overview of Creating and Using Dynamic Link Libraries

Dynamic Link Libraries, or DLLs for short, are essential components in Windows operating systems. They are small programs that can be shared between different applications, which makes them an incredibly important part of software development. A DLL contains code, data, and resources that are required by other programs to perform specific functions. In this article, we will look at the basics of creating and using dynamic link library.

Dynamic Link Libraries (DLLs) are shared libraries that are commonly used in various programming languages to contain a collection of reusable code and data. Unlike static libraries, DLLs provide immense benefits such as runtime flexibility, which makes them an essential component of modern applications. These libraries can be used by multiple applications simultaneously, thus saving system resources and memory. In this blog post, we will dive into the concept of DLLs, how they work, and their benefits. We will also explore the steps involved in creating and using DLLs in your projects.

What are Dynamic Link Libraries?

DLLs are binary files consisting of reusable code and data, dynamically linked to an application during runtime. When an application gets launched, the operating system loads the required DLLs into memory and links them to the program, allowing the application to call functions contained within the DLL. DLLs are often used to contain code that performs a specific function and is reusable across multiple applications. This approach accelerates code development, reduces code duplication, and allows efficient use of system resources.

DLLs are essential parts of many Windows applications, and developers often create them to accomplish tasks that are common to many different applications. For example, a DLL can contain functions that perform calculations, create dialog boxes, or access system resources. By creating a DLL with these functions, developers can share the code between multiple applications, which reduces the amount of time and effort required to develop new applications.

To create a dynamic link library, you need to have a programming language that supports DLLs and an IDE or text editor to write the code. Once you have written the code, you can compile it into a DLL using the appropriate compiler and linker. It is important to make sure that the DLL is properly installed on the target system and registered with the operating system to be able to use it.

When using a DLL in an application, you need to include a reference to the DLL in your code and use the functions it contains. There are two ways to link with a DLL – static linking and dynamic linking. Static linking involves linking the code of the DLL directly into the application at compile time. Dynamic linking, on the other hand, involves linking to the DLL at runtime. Dynamic linking can be more flexible than static linking, but it requires the DLL to be properly installed and registered on the target system.

Advantages of using Dynamic Link Libraries

Dynamic Link Libraries provide numerous benefits to developers. One of the critical benefits is that DLLs can be loaded and unloaded into the memory as and when required, making them easy to maintain and update. Additionally, they enable efficient use of system resources, as multiple applications can use the same DLL, thus reducing memory usage. Developers can also create private DLLs that can be shared across projects, making code management more manageable. DLLs also play a vital role in accelerating application startup time. They are loaded into memory on-demand, thus reducing the application’s load time.

Dynamic link libraries can also be used to enforce security policies. By controlling the behavior of a DLL, you can prevent malicious code from running on the system. For example, a DLL can be designed to only allow certain types of input or to disallow certain types of behavior. This can help prevent malware from running on the system or prevent damage to critical files or components.

Another advantage of DLLs is that they can be updated independently of the applications that use them. This means that you can fix bugs or add new features to a DLL without having to recompile or redistribute the entire application. This can save time and reduce the risk of errors that can occur when redistributing a large application.

Steps to Creating Dynamic Link Libraries

Creating Dynamic Link Libraries in Visual Studio is pretty straightforward. In the Visual Studio IDE, developers can create a new project of a type Dynamic-Link Library to get started. Once the project template is created, developers can write the necessary code and build the project. After building the project, a DLL file gets created in the output or bin folder, along with a .lib import library. The .lib file acts as a proxy to the DLL, containing symbols that allow the application to call the DLL’s functions.


Dynamic link libraries are an important part of Windows programming, and they can be used to save time, reduce errors, and improve the security of an application. Developers can create DLLs to perform common tasks that can be shared between multiple applications, and they can be updated independently of the applications that use them. While there are some drawbacks to using DLLs, such as increased complexity and potential security vulnerabilities, they are a valuable tool that every Windows developer should learn to use.

Dynamic Link Libraries provides an efficient and flexible way to reuse code and simplify application development. Although they come with some nuances, DLLs offer several benefits that contribute to faster application development and optimized resource usage. In this blog post, we explored the concept of DLLs, their advantages, creating and using DLLs in your applications. Following best practices is also essential while creating DLLs to ensure optimal performance and maintainability in the long run. Many popular applications, including Microsoft Windows, rely on DLLs and will continue to do so. As a developer, it’s essential to have a strong understanding of how to effectively create and use DLLs to become a versatile programmer.