Newlib

Newlib is a C standard library implementation intended for use on embedded systems. It is a conglomeration of several library parts, all under free software licenses that make them easily usable on embedded products.

Newlib
Original author(s)	Cygnus Support
Developer(s)	Red Hat

Stable release	4.4.0 / December 31, 2023; 9 months ago (2023-12-31)^[1]

Repository	sourceware.org/git/newlib-cygwin.git
Operating system	Cross-platform^{[citation needed]}
Type	Runtime library
License	Various MIT/BSD-like licenses
Website	www.sourceware.org/newlib/

It was created by Cygnus Support as part of building the first GNU cross-development toolchains. It is now maintained by Red Hat developers Jeff Johnston and Corinna Vinschen, and is used in most commercial and non-commercial GCC ports for non-Linux embedded systems.

System Calls

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The section System Calls^[2] of the Newlib documentation describes how it can be used with many operating systems. Its primary use is on embedded systems that lack any kind of operating system; in that case it calls a board support package that can do things like write a byte of output on a serial port, or read a sector from a disk or other memory device.

Inclusion

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Newlib is included in commercial GCC distributions by Atollic, CodeSourcery, Code Red, KPIT, Red Hat and others, and receives support from major embedded-processor architecture vendors such as ARM and Renesas. It is used as the standard C library in Cygwin, as well as being one standard C library among several for AmigaOS 4.

As of 2004^[update], KallistiOS, an independent SDK targeting the Sega Dreamcast, has used Newlib as its standard C library, shipping it with many commercial titles on the platform.^[3]

As of 2007^[update], devkitARM and devkitPPC, toolchains targeted at homebrew development for commercial game systems, include Newlib as their C library. The Open-R SDK for Sony AIBO is also based on Newlib on top of the non-Unix Aperios.

As of 2013^[update], Google Native Client SDK (NaCl) includes Newlib as the default C library over glibc.^[4]

In 2019, Keith Packard released Picolibc,^[5] a library offering standard C library APIs that targets small embedded systems with limited RAM, based on blending code from Newlib and AVR Libc.