Binary File Descriptor library

The BFD, or Binary File Descriptor library, is the GNU Project's main mechanism for the portable manipulation of object files in a variety of formats. As of 2003, it supports approximately 50 file formats for some 25 processor architectures.

BFD works by presenting a common abstract view of object files. An object file has a "header" with descriptive info; a variable number of "sections" that each have a name, some attributes, and a block of data; a symbol table; relocation entries; and so forth.

Internally, BFD translates the data from the abstract view into the details of the bit/byte layout required by the target processor and file format. Its key services include handling byte order differences, such as between a little-endian host and big-endian target, correct conversion between 32-bit and 64-bit data, and details of address arithmetic specified by relocation entries.

Although BFD was originally designed to be a generic library usable by a wide variety of tools, its licensing under the GPL, and the frequent need to tinker with the API to accommodate new systems' capabilities has tended to limit its use; BFD's main clients are the GNU Assembler (GAS), GNU Linker (GLD), and other GNU Binary Utilities ("binutils") tools, and the GNU Debugger (GDB). As a result, BFD is not distributed separately, but is always included with releases of binutils and GDB. Nevertheless, BFD is a critical component in the use of GNU tools for embedded systems development.

The BFD lib can be used to read the structured data out of a Core Dump.


When David Henkel-Wallace of Cygnus Support proposed developing the library, as a way to open up new business opportunities for the company, Richard Stallman said (correctly) that it would be difficult; David's response was "BFD" (big fucking deal). This became the library name, [cite web
title = Binary File Descriptor Library manual — History
month = August
year = 2007
publisher = GNU Project
url =
accessdate = 2008-04-08
quote = The name came from a conversation David Wallace was having with Richard Stallman about the library: RMS said that it would be quite hard—David said "BFD". Stallman was right, but the name stuck.
] and "Binary File Descriptor" was invented later as the meaning of the letters.


External links

* [ Binutils page, with access to current BFD sources]

Wikimedia Foundation. 2010.