What Is an SO File?

The basics of using a shared library file

What to Know

  • An SO file is a shared library file used on Android and Linux operating systems.
  • Several programs can use the same SO file.
  • It's not meant to be opened manually, but you might have luck doing so with the GCC.

This article explains what SO files are, including why and where they're used.

What Is an SO File?

A file with the .SO file extension is a shared library file. They contain information that can be used by one or more programs to offload resources so that the application(s) calling the SO file doesn't have to actually provide the file.

For example, one SO file might contain information and functions on how to quickly search through the whole computer. Several programs can then call upon that file to use that feature in their own respective programs.

Screenshot of SO files in Ubuntu

However, instead of having to compile it in the program's own binary code, the SO file serves as an extension that the program just has to call on in order to use its utilities. The SO file can even be updated/replaced later without those programs having to make any changes to their own code.

Shared library files are similar to Dynamic Link Library (DLL) files used in Windows and Mach-O Dynamic Library (DYLIB) files on macOS, except that SO files are found on Linux-based systems and the Android OS.

SO doesn't just refer to a shared library file. It's also an abbreviation for server options, service object, system overload, send only, system outage, serial output, and stuck open. However, don't confuse it with OS, which means operating system.

How to Open a SO File

SO files can technically be opened with the GNU Compiler Collection (GCC), but these types of files aren't intended to be viewed or used like you might another file type. Instead, they're just placed in an appropriate folder and used automatically by other programs via Linux's dynamic link loader.

However, you might be able to treat it as a text file by opening it in a text editor like Leafpad, gedit, KWrite, or Geany if you're on Linux, or Notepad++ on Windows. It's unlikely, though, that the text will be in a human-readable format.

How to Convert SO Files

We're not aware of any programs that can convert SO to DLL for use on Windows, and considering what these files are and what they do, it's not likely there's one out there. It's also not a straightforward task to convert SO to other file formats like JAR or A (a Stat Library file).

You might be able to "convert" SO files to JAR files by just zipping them into an archive file format like .ZIP and then renaming it to .JAR.

Still Can't Open the File?

An obvious reason for why you can't open the file is that it's not really a SO file. It might just share some common letters as that file extension. Similar sounding file extensions don't necessarily mean that the file formats are similar, nor that they might work with the same programs.

For example, the popular ISO file format looks a lot like it reads ".SO" at the end of the filename, but the two are not related and can't open with the same programs.

Another example can be seen with SOL files, which are Flash local shared objects used with the now-defunct Adobe Flash.

More Information on SO Files

The name of a shared library file is called a soname. It starts with "lib" at the beginning, followed by a name for the library and then the .SO file extension. Some shared library files also have other numbers appended to the end after ".SO" to indicate a version number.

Here are just a few examples: libdaemon.SO.14, libchromeXvMC.SO.0, libecal-1.2.SO.100, libgdata.SO.2, and libgnome-bluetooth.SO.4.0.1.

The number at the end allows there to be multiple versions of the same file without causing issues with overlapping names. These files are normally stored in /lib/ or /usr/lib/.

On an Android device, SO files are stored within the APK under /lib//. Here, "ABI" can be a folder called armeabi, armeabi-v7a, arm64-v8a, mips, mips64, x86, or x86_64. The SO files within the correct folder that pertains to the device, are what's used when the apps are installed via the APK file.

Shared library files are sometimes called dynamically linked shared object libraries, shared objects, shared libraries, and shared object libraries.

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