The object package provides a unified interface for working with object files across platforms. It supports reading relocatable object files and executable files, and writing COFF/ELF/Mach-O/XCOFF relocatable object files and ELF/PE/Mach-O executable files.

For reading files the library provides various abstraction levels:

• raw type/record definitions close to the original C definitions
• low level APIs for accessing specific formats
• a higher level unified API for accessing common features of object files, such as sections and symbols

Supported file formats for reading: ELF, Macho-O, Windows PE/COFF, and Unix Archive.

For writing files the library provides:

• low level writers for ELF, Mach-O, and PE/COFF.
• higher level builder for ELF
• a unified API for writing relocatable object files (ELF, Mach-O, COFF)

To install object as a dependency, run:

$ opam install object

And add object to your project's dune-project or *.opam files.

• Documentation on ocaml.org
• Example programs in example directory
  • A simple file implementation that checks for MAGIC numbers
  • A simple objdump implementation for displaying the section headers.
  • Implementation of nm to display name list (aka symbol table).
  • Implementation of otool the object file displaying tool for MachO binaries
  • Implementation of lipo for creating or operating on universal files (aka FAT binaries).

This motivation for this library grew out of the author's need to manipulate object files and DWARF information while working on the OCaml compiler. The library name simultaneously derives from the author's fascination with objects in OCaml and the Rust library of the same name.