Filename Extensions
If you are seeking information about file extensions, then you are in the right place at right time.

Details of extension .o

1 extension(s) and 0 alias(es) in our database

Below, you can find answers to the following questions:

  • What is the .o file?
  • Which program can create the .o file?
  • Where can you find a description of the .o format?
  • What can convert .o files to a different format?
  • Which MIME-type is associated with the .o extension?
Compiled Object File .o file icon

Compiled Object File

The O file is a Compiled Object. The Compiled Object file is the representation of code that a compiler or assembler generates by processing a source code file. Object files contain compact code, often called "binaries". A linker is typically used to generate an executable or library by linking object files together.
Category: Development files
Program name: -
Mime-type: application/octet-stream
Magic bytes (HEX): -
Magic string (ASCII): -
Related extensions:
C Source Code
Windows Command File
Executable File
Unix AR Archive
Interface Definition File
Unix Shared Library
Linux 2.6 Kernel Object
Visual C++ Preprocessed Source
INTERCAL Source File

Other types of files may also use the .o file extension. If you have helpful information about .o extension, write to us!

Can't open a .o file?

If you want to open a .o file on your computer, you just need to have the appropriate program installed. If the .o association isn't set correctly, you may receive the following error message:

Windows can't open this file:

File: example.o

To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select from a list of programs that are installed on your computer.

To change file associations:

  • Right-click a file with the extension whose association you want to change, and then click Open With.
  • In the Open With dialog box, click the program whith which you want the file to open, or click Browse to locate the program that you want.
  • Select the Always use the selected program to open this kind of file check box.

Supported operating systems

Windows Server 2003/2008/2012/2016, Windows 7, Windows 8, Windows 10, Linux, FreeBSD, NetBSD, OpenBSD, Mac OS X, iOS, Android