What is dll in linux

What is a dll?

This may be a very noobie question, but in today’s world of web app development many programmers don’t need to deal with dll’s much, and thus don’t bother to learn about their purpose.

So what is a dll?

1. What is it used for?
2. How does it work?
3. How do you create one?
4. In what situations is creating one appropriate?

I’ve been told that dll’s are used to store libraries of functions, but beyond that I don’t know much. Hopefully someone here can enlighten me so I can finally stop wondering what all those .dll files in my Windows directory are doing.

6 Answers 6

A DLL is a dynamic link library. It is a collection of code and/or data, which may be used by several applications (or other libraries/modules).

So for instance common methods to process files, work with GUI components etc. are made available in libraries so several applications may use the same functionality. This not only reduces the need to build the same stuff multiple times, but it also ensures that e.g. common dialogs are the same between applications.

Libraries can be loaded at runtime and thus shared between different concurrent applications. This is called dynamic linking.

In some cases the library can be included within the application itself. This is known as static linking. Static linking makes deployment easier at the cost of flexibility as different application will each load the same copy of the DLL.

However, static linking is not always an option. E.g. you can’t statically link a .NET application. The user must have the .NET libraries in order to run a .NET application and libraries (or assemblies as they are called in .NET) are loaded at runtime.

DLLs are created by the same tools used to create applications. The specific details depend very much on the tools used.

DLL = Dynamic Link Library

The name is actually quite descriptive of what they accomplish.

Library

Lets you isolate code for a specific problem domain into a single location. Then share this among multiple applications. The library can be swapped out for another at any time to fix bugs or add functionality.

Link

You can «Link» the library to an application so that the logic in the library is not compiled directly into the application.

Dynamic

The library can be loaded on-demand. Instead of loading a mammoth single EXE into memory, the OS can load only the portions needed. Plus if a DLL is shared between applications, the OS can optimize how the library is loaded and share it between apps.

DLL (dynamic link library) files can be described as small «sub-programs» which are meant to help a bigger program run well. They provide a means of linking various hardware and software resources (at various points in its run-time sessions) to the main executable program upon which they are based, on an «as-the-need-arises» basis. This eliminates the need to load everything to do with the main executable program onto the computer’s RAM (random access memory) when the program is first ran.

The software resources carried by DLLs include code for the various program functions that aren’t really needed to keep the program running: that is, functions that only need to be called upon at certain times during a given computing session and might actually not even need to be called at all. Loading those functions (and there can be a considerable number of them for a given program) onto the computer’s RAM when the program is first ran and then keeping them there throughout the session would be a waste of RAM space — which is considered to be at a premium.

A major advancement:

The development of DLLs was a major advancement in computing, because before they were available, everything to do with a program (including functions that were rarely if ever used) had to be loaded onto the RAM when the program was first loaded. That led to extremely inefficient computing, with slower speeds exhibited by various programs. It was also extremely hard to multitask by running even a couple of simple programs, because of the attendant strain on the RAM.

DLLs are usually version-specific. Those that work well for, say, Version 1 of a program (or a programming language, as may be the case) might not work well with Version 2. The general rule is that the DLLs in the older version tend to be unable to work well with the newer version, but those of the newer version can generally work quite well with the older version of the program or programming language.

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What is DLL in Linux?

A DLL (Dynamic Link Library) is a binary software component (essentially a file) that has data, classes and functions compiled into it in the form of being callable from an executable binary file (EXE).

Does Linux use DLL?

In Linux, plugins and dlls are implemented as dynamic libraries. The remainder of this article is an example of using dynamic libraries to change an application after the application is running.

What is a DLL and how does it work?

A DLL is a library that contains code and data that can be used by more than one program at the same time. For example, in Windows operating systems, the Comdlg32 DLL performs common dialog box related functions. … Each module can be loaded into the main program at run time if that module is installed.

How do I open a DLL file in Linux?

A “DLL” usually mean a “dynamically linked library”. So the only way you “open a DLL file in Linux” is by providing all the link references the DLL consumes.
…

1. Open Chrome on your computer.
2. Click Chrome Remote Desktop . …
3. Click the Access button.
4. Enter the access code provided by your friend.
5. Click Connect.

What DLL means?

DLL, in full dynamic link library, a file containing code for commonly used program functions on personal computers (PCs) that run the Microsoft Corporation’s Windows operating system. DLL. Operating system.

How do I read a DLL file?

If you are using Windows 7 or newer, open the folder containing the new DLL file, hold the Shift key and right-click in the folder, and select “Open command window here”. The Command Prompt will open directly to that folder. Type regsvr32 dllname . dll and press Enter.

What is the purpose of a DLL?

Dynamic Link Library (DLL) is Microsoft’s implementation of the shared library concept. A DLL file contains code and data that can be used by multiple programs at the same time, hence it promotes code reuse and modularization. This brief tutorial provides an overview of Windows DLL along with its usage.

How do I install a DLL file?

dll file should now be part of Windows. This story, “Add a missing .
…
dll files to your Windows operating system.

1. Locate your missing . dll file at the DLL Dump site.
2. Download the file and copy it to: “C:WindowsSystem32”
3. Click Start then Run and type in “regsvr32 name_of_dll. dll” and hit enter.

How do you create a DLL file?

1. Click the File. …
2. Click New and Project. …
3. Set the options for Language, Platform, and Project Type. …
4. Click Platform to get a drop-down menu and click Windows.
5. Click Project Type to get a drop-down menu and click Library.
6. Click Dynamic-link Library (DLL). …
7. Type a name in the Name Box for the project. …
8. Click Create.

How do I open DLL files to edit?

Part 2 of 2: Editing DLLs with Hex Editor

1. Install the Hex Editor. …
2. Click File. …
3. Select Open. …
4. Click Open File…. …
5. Find the DLL you want to edit. …
6. Select the DLL. …
7. Click Open. …
8. Edit the DLL’s contents.

What is DLL in teaching?

Daily Lesson Log (DLL) is a template teachers use to log parts of their daily lesson. The DLL covers a day’s or a week’s worth of lessons and contains the following parts: Objectives, Content, Learning Resources, Procedures, Remarks and Reflection.

What language is DLL written in?

DLL files use languages like C or C++, although you’ll see C++ more often. You can write your own DLLs to run some code you need if you’re willing to learn how to do it.

Should I delete DLL files?

dll Files are installed by software programs while they are installed These files contain code that tells programs how to operate. If you delete . dll files programs may not work properly. We suggest you not to delete these files as they may cause serious issues with the proper functioning of the computer.

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Possible to use a .dll on Linux [duplicate]

Question: Is it possible to compile a program on linux using a .dll file?

Where this is going: This .dll will be used to write a php extension to some proprietary software from a third party.

Background and Research:

I have been given a library called proprietary.lib . I was curious, as I have never seen the .lib extension before, so I typed:

I did some research and found that ar is more-or-less tar (and in fact, I guess tar has since replaced ar in most *nix environments).

Upon inspecting the ar manpage, I saw the t option , which displays a table listing of the contents of that archive. Cool. So I type:

5 Answers 5

Recent development may have changed the situation: There is a loadlibrary function for Linux available, that makes it possible to load a Windows DLL and then call functions within.

So, if the .dll file you have actually is a Windows DLL, you may find a way to use it in you software.

.dll files are usually Windows shared libraries. (It’s also possible that somebody on Linux has built a regular Linux library and called it .dll for some reason.)

It’s possible you could link against them using Wine. Support for this was once in there as experimental — I don’t know its current status.

You could try extracting the ar file (Debian packages are ar files, fwiw) and run file on the contents.

You’re not going to be able to use Windows DLLs without translation. The only DLL files that I know of that work natively on Linux are compiled with Mono.

If someone gave you a proprietary binary library to code against, you should verify it’s compiled for the target architecture (nothing like trying to use am ARM binary on an x86 system) and that it’s compiled for Linux.

That being said. good luck. I hate programming against third-party libraries where I have the documentation and the source.

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What are .dlls doing in Linux programs?

Games that were made with Unity3D for Linux contains .dll files in their data folder GameDataFolder/Managed .

Which is weird because I thought that Linux uses .so files instead of .dll files.

(The same is true for Android-Unity3D apps too.)

2 Answers 2

The games you are speaking about are based on the .NET Framework and running with Mono, which is a free and open-source implementation of Microsoft’s .NET Framework.

Because these applications are .NET based, Assemblies have .dll extension. So you can see DLL files in the folders.

One .NET program designed for cross-platform use can run on Windows, Linux or Mac, with the same «binaries» (including DLLs which are also assemblies), which are compiled in MSIL and need a .NET/Mono runtime to be executed.

Please note that you also have some free applications (not only games) based on Mono Framework available in Ubuntu repositories. For example: Tomboy.

The .dll files in GameDataFolder/Managed belong to a native code program that uses Mono internally.

The Unity game engine embeds Mono (even on most Windows platforms).

Cross-platform executables and shared libraries that can be run either by the .NET Common Language Runtime or Mono are often named with .exe and .dll suffixes, respectively, even when they are not specific to Windows. When you find a .dll file in a program for a GNU/Linux system like Ubuntu, or for any OS but Windows, this is usually why. Most of the time you find a .dll in an Ubuntu system, Golboth’s answer explains it. But that’s not quite what’s going on here.

The Unity game engine—which should not be confused with the default graphical interface in most Ubuntu releases—is a popular proprietary cross-platform game engine. This engine does not run on top of the .NET Framework or Mono. Instead, it embeds Mono, which is to say that Mono runs on top of it. This is how developers write whatever code their game needs that is not already part of the Unity engine.

In general, Mono may be used the same way Microsoft’s .NET CLR is usually used, to run complete .NET/Mono programs. But Mono is also designed to be easily embeddable in native code applications, including to enable those applications to be customized. That’s what’s going on in the situation you are describing. The files you’re seeing do not belong to a program that runs directly on top of Mono or the .NET CLR. Instead they belong to a native-code program that embeds Mono.

How the Unity Game Engine Uses Mono

The Unity game engine, which is written mostly in C++, hosts its own instance of Mono, which does not use—and may be different from—the version (if any) installed through your system’s package manager. This embedded Mono runtime cannot be used to run standalone .NET/Mono programs, because that is not its purpose. Instead, the native code portion of the engine uses it to run CIL code. (CIL is Common Intermediate Language, which is its official name. It was previously called MSIL or Microsoft Intermediate Language, since Microsoft developed it originally.) Programmers making games that use the Unity engine usually write their own code in C#, though some other languages are supported.

The Unity engine embeds Mono even in Windows. For Universal Windows Platform games—and no other platforms—it uses the Microsoft .NET Framework instead of Mono. But the majority of Unity games on most platforms, including most mobile devices and gaming consoles, and including Ubuntu and Windows, use Mono. On some platforms IL2CPP is available as an alternative to Mono, and on a few only IL2CPP is supported. See Scripting restrictions for details.

Other Situations Where You May See .dll Files On Ubuntu

Two situations where you are likely to see a .dll file on Ubuntu have been described:

1. A shared library that is intended to be used by a .NET/Mono application. Golboth’s answer describes this in detail. This is what most .dll s you’ll see on an Ubuntu system are. It just does not happen to be what the .dll files in your GameDataFolder/Managed folder are for.
2. A file providing code that is used by an embedded Mono runtime to provide «scripting» for a native code application. That’s what’s going on in this case.

There are two other reasonably common cases where you may see a .dll file on Ubuntu:

1. The compiler for .NET Core produces .dll files rather than .exe files, even when what you are compiling is not a library. The .NET Core runtime (called CoreCLR), and not the regular .NET Framework or Mono, runs these files. .NET Core is a Microsoft product, but unlike the standard .NET Framework, .NET Core is cross-platform with official support for GNU/Linux systems like Ubuntu, and it is free open source software.
2. Sometimes a .dll file you see on Ubuntu will just be a Windows library. You may see this if the program is being stored an Ubuntu system but run on Windows, or if you mount a Windows drive in Ubuntu. You may also see it in connection with programs that are able to be run on Ubuntu using Wine, including software that comes with Wine or that you install automatically with winetricks to support other Windows software.

This is not an attempt to exhaustively list all the circumstances where you may encounter a .dll on Ubuntu. (For example, it could also be an OS/2 library.) However, I believe those four cases are the most common ones.

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