UClibc
Encyclopedia
In computing
, uClibc is a small C standard library
intended for embedded Linux
systems. uClibc was created to support uClinux
, a version of Linux not requiring a memory management unit
and thus suited for microcontroller
s (uCs; the "u" is a romanization
of μ for "micro").
The project lead is Erik Andersen. The other main contributor is Manuel Novoa III. Licensed under the GNU Lesser General Public License
, uClibc is free software
.
, the C library normally used with Linux distributions. While glibc is intended to fully support all relevant C standards across a wide range of hardware and kernel platforms, uClibc is specifically focused on embedded Linux. Features can be enabled or disabled according to space requirements.
uClibc runs on standard and MMU
-less Linux systems. It supports i386, x86-64
, ARM
(big/little endian), AVR32
, Blackfin
, h8300
, m68k, MIPS
(big/little endian), PowerPC
, SuperH
(big/little endian), SPARC
, and v850
processors.
Computing
Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...
, uClibc is a small C standard library
C standard library
The C Standard Library is the standard library for the programming language C, as specified in the ANSI C standard.. It was developed at the same time as the C POSIX library, which is basically a superset of it...
intended for embedded Linux
Embedded Linux
Embedded Linux is the use of Linux in embedded computer systems such as mobile phones, personal digital assistants, media players, set-top boxes, and other consumer electronics devices, networking equipment, machine control, industrial automation, navigation equipment and medical instruments...
systems. uClibc was created to support uClinux
UClinux
μClinux stands for "MicroController Linux," and is pronounced "you-see-Linux" as explained on the website, not the way the Greek letter mu is normally pronounced. It was a fork of the Linux kernel for microcontrollers without a memory management unit...
, a version of Linux not requiring a memory management unit
Memory management unit
A memory management unit , sometimes called paged memory management unit , is a computer hardware component responsible for handling accesses to memory requested by the CPU...
and thus suited for microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
s (uCs; the "u" is a romanization
Romanization
In linguistics, romanization or latinization is the representation of a written word or spoken speech with the Roman script, or a system for doing so, where the original word or language uses a different writing system . Methods of romanization include transliteration, for representing written...
of μ for "micro").
The project lead is Erik Andersen. The other main contributor is Manuel Novoa III. Licensed under the GNU Lesser General Public License
GNU Lesser General Public License
The GNU Lesser General Public License or LGPL is a free software license published by the Free Software Foundation . It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License...
, uClibc is free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
.
Features
uClibc is much smaller than the glibcGNU C Library
The GNU C Library, commonly known as glibc, is the C standard library released by the GNU Project. Originally written by the Free Software Foundation for the GNU operating system, the library's development has been overseen by a committee since 2001, with Ulrich Drepper from Red Hat as the lead...
, the C library normally used with Linux distributions. While glibc is intended to fully support all relevant C standards across a wide range of hardware and kernel platforms, uClibc is specifically focused on embedded Linux. Features can be enabled or disabled according to space requirements.
uClibc runs on standard and MMU
Memory management unit
A memory management unit , sometimes called paged memory management unit , is a computer hardware component responsible for handling accesses to memory requested by the CPU...
-less Linux systems. It supports i386, x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...
, ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
(big/little endian), AVR32
AVR32
The AVR32 is a 32-bit RISC microprocessor architecture designed by Atmel. The microprocessor architecture was designed by a handful of people educated at the Norwegian University of Science and Technology, including lead designer Øyvind Strøm, PhD and CPU architect Erik Renno, M.Sc in Atmel's...
, Blackfin
Blackfin
The Blackfin is a family of 16- or 32-bit microprocessors developed, manufactured and marketed by Analog Devices. The family is characterized by their built-in, fixed-point digital signal processor functionality supplied by 16-bit Multiply–accumulates , accompanied on-chip by a small and...
, h8300
H8 Family
H8 is the name of a large family of 8-bit and 16-bit microcontrollers made by Renesas Technology, originating in the early 1990s within Hitachi Semiconductor and still actively evolving as of 2006...
, m68k, MIPS
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...
(big/little endian), PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
, SuperH
SuperH
SuperH is a 32-bit reduced instruction set computer instruction set architecture developed by Hitachi. It is implemented by microcontrollers and microprocessors for embedded systems....
(big/little endian), SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....
, and v850
V850
The Renesas Electronics V850 is a 32-bit RISC CPU core architecture for embedded microcontrollers originally developed and manufactured by NEC, succeeded by V850 variants named V850ES, V850E, and V850E2 which run uClinux. Compilers available for it include the GNU Compiler Collection, IAR Systems...
processors.
Buildroot
Buildroot is a set of scripts and patches for easing the generation of a cross-compilation chain as well as the creation of a file system.History
Development on uClibc started around 1999. uClibc was mostly written from scratch, but has incorporated code from glibc and other projects.See also
- Alpine LinuxAlpine LinuxAlpine Linux is a Linux distribution based on uClibc and BusyBox, which has the goal of being lightweight and secure by default while still being useful for general-purpose tasks. Alpine Linux uses PaX and grsecurity patches in the default kernel and compiles all packages with stack-smashing...
- busyboxBusyBoxBusyBox provides several stripped-down Unix tools in a single executable. It runs in a variety of POSIX environments such as Linux, Android, FreeBSD and others, such as proprietary kernels, although many of the tools it provides are designed to work with interfaces provided by the Linux kernel. It...
- ContikiContikiContiki is a small, open source, highly portable multitasking computer operating system developed for use on a number of memory-constrained networked systems ranging from 8-bit computers to embedded systems on microcontrollers, including sensor network motes...
- dietlibcDietlibcdietlibc is a C standard library released under the GNU General Public License Version 2. It was developed by Felix von Leitner with the goal to compile and link programs to the smallest possible size. dietlibc was developed from scratch and thus only implements the most important and commonly used...
- OpenWrtOpenWrtOpenWrt is a Linux distribution primarily targeted at routing on embedded devices. It comprises a set of about 2000 software packages, installed and uninstalled via the opkg package management system. OpenWrt can be configured using the command-line interface of BusyBox ash, or the web interface...
- Tor-ramdiskTor-ramdiskTor-ramdisk is an i686 uClibc-based micro Linux distribution whose only purpose is to host a Tor server in an environment that maximizes security and privacy. Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet...
— uClibc-based Linux distribution - T2 SDE — supports cross compilation of Linux systems, including uClibc