DLL files: What are they? What are they for?

What are you going to find here? Definition of DLL files and what they are for. How to install, open and handle them.

These DLL files are essential for the proper functioning of the applications, since they are part of them, since they contain various elements such as graphics, fonts, commands and others.

As we mentioned, DLL files are unfortunately related to errors on the PC, this happens due to poor execution of them due to the programmer’s carelessness or due to poor design of the program that uses these DLLs. This causes that once the application that uses them is closed, the DLLs continue to reside in the memory, which in addition to harming us in terms of the performance of our computer, raises compatibility problems.

What is a DLL file?

The DLL files, acronym for its name in English Dynamic Link Library, known in Spanish as Libraries of Dynamic Links, consist of a series of files that consist of executable code and other parts of an app, which make it possible to use the applications that we have installed on the PC.

When we order our team to execute a program, without our noticing it, the operating system automatically loads the corresponding DLL library so that the application or function included in the app is executed.

Although in general, DLL files are related to the Microsoft Windows operating system , the truth is that all operating systems use these types of libraries to run applications.

It should be noted that beyond the fact that many users refer to DLLs as files that slow down the operation of the PC , the truth is that they are very useful, so they have a large number of advantages to perform the usual tasks on the computer , as we can see below these lines.

What are DLL files for?

In principle, one of the most important advantages that DLL files or dynamic link libraries offer us is that thanks to their implementation it has been possible to significantly reduce the size of the executable files of the applications, since a large portion of the codes Program executables can be stored in these DLL files, such as graphics, audio, text, typography and all the other elements used by the app, thus obtaining a greater organization of the processes, which results in a better performance of the app, and therefore of the general performance of the computer.

However, DLL files also offer other very interesting advantages, more related to the performance of computer parts, since for example, many times the same dynamic link library or DLL can be used by different programs, such as This is the case of the so-called MFC, which is usually used by a large number of applications that run on the Windows operating system.

DLL files also make it possible to increase the use of memory and facilitate the management through the application of certain algorithms that help improve the performance of the operating system and increase the speed during the execution of applications that use the same DLL libraries, since that have been loaded previously.

Errors and DLL files

As we mentioned at the beginning of this post, DLL files are closely related to errors in the operating system such as the dreaded blue screens of death, system crashes, spontaneous reboots, and other calamities. However, the truth is that DLL libraries are not the culprits per se, but the developers of said DLLs do not take the trouble to design them taking into account all possible hardware and software conditions, that is, they test and use them in areas where everything works perfectly, but then on the user’s PC, with its complexity of apps and others, the scenario is another.

DLL libraries have been tested over the years, and they have given ample evidence that they are one of the best tools that the programmer has to develop well-made applications, that is, they do not use more RAM memory or system resources of those strictly necessary.

If the programmer does not comply with these premises, the most probable thing is that the DLL files that he develops have faults and problems of all kinds, which will immediately be transferred to the work of the user who uses his program.

Despite all this, it is always possible to correct and rewrite a DLL file to solve the problems that users have reported, in fact it is one of the easiest ways to achieve this is through updates, in which new ones are introduced Advances in dynamic libraries, making it possible to correct reported errors. All this is thanks to the flexibility that characterizes DLL files.

However, this advantage can sometimes lead to inconveniences, caused by a possible incompatibility of the programs with the new updated dynamic libraries, which result in crashes that can prevent the execution of an application.

However, these problems are constantly being solved, for which users are usually made available to download updated and compatible DLL files.

Install DLL files

Although the scenarios in which the user has to install a DLL file manually are scarce, since its execution and use are transparent and occur in the background for the user, the truth is that it may be necessary, especially in apps that they are no longer supported by the developer.

To install a DLL file on our computer easy, all we have to do is follow the steps given below.

Step 1

The first thing we have to do to successfully install a DLL library is to know the exact name of the DLL file we need. This is normally simple, and the app itself will be in charge of asking us for the file that is missing to function normally. Another way to get the name of the missing DLL is by consulting Google or another search engine. Once we find it, we download it to our computer, always taking into account the reputation of the site from which we are going to do it, for security reasons.

Once we have it, we write it down somewhere at hand. For the sake of this tutorial, our DLL library will be called “DLLLibrary.dll.”

Step 2

We follow the steps indicated by the site to download the DLL file, and then we select the location, preferably easily accessible. Under no point of view should we change the name of the DLL library that we just downloaded.

If the DLL file is compressed into a ZIP or RAR file, we must unzip it.

Step 3

Once the RAR or ZIP file containing the DLL library has been decompressed, we right-click on it and select the option, “Copy”.

Step 4

Once this is done, we move to the following location on the disk: “C: \ Windows \ system32”. There, in any clear place in the window, we click with the right mouse button and select the option “Paste”. With this we have just copied the DLL file into the Windows registry folder.

In the event that Windows shows us a notification regarding the copy permissions, we allow the action.

Step 5

Now, we move to the “Start” menu . There we write “regsvr32”, followed by the name of the DLL file that we want to install. That is, for the example it would be something like this: “regsvr32 C: \ windows / system32 / libraryDLLdll”. We must write this without quotes.

This action will run the Windows registry, after which the DLL file that we just entered will be registered.

It should be noted that this procedure is similar in any of the Windows versions.

Open DLL files

Before we start, we must understand that trying to open a DLL file can be harmful to our computer, and we could even damage it. In the best case when trying to open a DLL with a tool like Windows Notepad, we will only get garbled characters.

Step 1

The first thing we have to do to open a DLL file is to open any folder in Windows, and then in its menu select the option “Folder options”, then look for the option “View” and finally click on “Show hidden files” and “Hide protected system files .” When we finish, click on the “Accept” button .

Step 2

After that, click on “Start” and select the “Search” option . Next we tell the system to look for “dll” files throughout the system. In some versions of Windows we can make use of the option “Search in all files and folders”.

Step 3

After this procedure, the system will return a list with all the DLL libraries it finds. At this point we click on the DLL library that we want to open and select the tool with which we want to do it.

How to view and modify DLL files

In the event that we need to edit a DLL in a more appropriate way, and for that we need to have programming knowledge, then we will need specialized tools to open DLLs, such as dotPeek, in addition to Visual Basic and other software development apps.

If you want to know how to modify a DLL file , all you have to do is follow the instructions given below.

Step 1

The first thing we have to do is decompile the DLL file that we want to edit. For this we need to download and install a decompiler. Basically, a decompiler is a programming application that enables us to see the source code of a program.

As we know, the content of a binary file is impossible for us to see or consult with tools such as text editors such as Windows Notepad, that is why in order to see the source code of an app or DLL file we need a decompiler, whose main task is to revert binary code to readable text and instructions.

In this sense, one of the most popular decompilers is dotPeek, which we can download for free by clicking on this link. Also for this example we will use this application.

Step 2

Q = To modify a DLL file, we have to open it in the decompiler. To do this we scroll to “File”, then click on “Open” and finally we navigate to the location of the DLL file that we want to edit.

At this point it should be noted that we can see the contents of a DLL file without any danger to the system.

Step 3

Once the DLL file is open, we can navigate through the different categories of objects that the DLL file incorporates using the compilation explorer, which will allow us to see the content of the different modules of the DLL library.

To see the content of the modules of the DLL file that we want, we can expand each node by double-clicking on them, which will also give us access to the other subnodes that the DLL file may contain.

Step 4

When we click on one of these nodes, its code will appear in the panel located to the right of the dotPeek interface . At this point, dotPeek displays the code in C #. In the case of wanting to see the DLL code in other languages, we can download additional libraries to add these options, or let dotPeek download and install these libraries automatically.

Step 5

Finally, and in order to modify and compile the DLL file again, we export the code to Visual Basic. It should be noted that the exported code will be in the C # language, even if the DLL code is written in a different language.

Step 6

To export the code of the DLL file, we move to the compilation explorer, click on the node that we want to export and click on the option “Export to Project” and select the relevant export options.

Step 7

To finish, we open the DLL code in Visual Studio and edit it. The only thing left to create our own DLL is to compile and install it as we saw earlier in this post.