OW File

What are OW files and how to open them

Are you having problems opening an OW file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your OW files.

What is an OW file?

An .OW file is a Free Pascal Compiled Object file.

Free Pascal Compiled Object files (with extension .ow) are intermediate binary files produced by version 1.0.x of the Free Pascal compiler. They hold compiled machine code and symbol information corresponding to a Pascal or Object Pascal program or unit, but are not yet linked into a final executable. After generation, the compiler's linker combines one or more .ow files (usually together with unit description files and other .ow files) to build the complete executable or library.

These files are not intended to be opened or edited by users; they are part of the compilation pipeline internal to Free Pascal 1.0.x. In that version, when a source file or unit is compiled, a .ow object file is generated, then the linker uses it along with others to resolve external references and produce an executable. Later versions of Free Pascal replaced .ow with .o for object files.

Technical signature details are not widely published. The files are in a proprietary internal object format used by Free Pascal 1.0.x, stored in binary form, and specific internal identifiers or byte signatures have not been confirmed in documented sources in recent references.

How to open OW files

We have identified one OW opener that is compatible with this specific type of OW file.

Programs that open Free Pascal Compiled Object files

Last updated: August 10, 2026

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