GNU libiberty is a software library

Library (computer science)

In computer science, a library is a collection of resources used to develop software. These may include pre-written code and subroutines, classes, values or type specifications....

 with a collection of subroutine

Subroutine

In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....

s used by various GNU

GNU

GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...

 programs

Computer program

A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

.

It was originally intended to be a sort of standard cross-platform

Cross-platform

In computing, cross-platform, or multi-platform, is an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computer platforms...

 library, thus enabling it to be linked (using the usual Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 library form) by just saying "-liberty". The contents consisted of a variety of useful functions. However, the development of standards for C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

 and POSIX

POSIX

POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...

 took away some of the impetus for this, and libiberty came to be used primarily as a support library for the GNU toolchain

GNU toolchain

The GNU toolchain is a blanket term for a collection of programming tools produced by the GNU Project. These tools form a toolchain used for developing applications and operating systems....

.

Copies of libiberty are distributed with gcc

GNU Compiler Collection

The GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...

, gdb

GNU Debugger

The GNU Debugger, usually called just GDB and named gdb as an executable file, is the standard debugger for the GNU software system. It is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Java...

, and the binutils.

One important piece of libiberty functionality is a demangler for C++

C++

C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...

, included so that it is available to both binutils

GNU Binary Utilities

The GNU Binary Utilities, or binutils, comprise a collection of programming tools for the manipulation of object code in various object file formats. The current versions were originally written by programmers at Cygnus Solutions using the Binary File Descriptor library...

 and GDB.

The name is a pun

Pun

The pun, also called paronomasia, is a form of word play which suggests two or more meanings, by exploiting multiple meanings of words, or of similar-sounding words, for an intended humorous or rhetorical effect. These ambiguities can arise from the intentional use and abuse of homophonic,...

 or word play

Word play

Word play or wordplay is a literary technique in which the words that are used become the main subject of the work, primarily for the purpose of intended effect or amusement...

 on the word "liberty

Liberty

Liberty is a moral and political principle, or Right, that identifies the condition in which human beings are able to govern themselves, to behave according to their own free will, and take responsibility for their actions...

". On Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, library files are always named "lib" + "the name of the library." But when they are linked to with a C compiler command (cc, gcc, etc.), the command line flag specifying the library is -l followed by the part of the library name after "lib". In libiberty's case it therefore becomes -liberty.