uClibc - a Small C Library for Linux
Erik Andersen <email@example.com>
uClibc (aka µClibc/pronounced yew-see-lib-see) is a C library for
developing embedded Linux systems. It is much smaller than the
GNU C Library, but nearly all applications supported by glibc
also work perfectly with uClibc. Porting applications from glibc
to uClibc typically involves just recompiling the source code.
uClibc even supports shared libraries and threading. It currently
runs on standard Linux and MMU-less (also known as µClinux)
systems with support for alpha, ARM, i386, i960, h8300, m68k,
mips/mipsel, PowerPC, SH, SPARC, and v850 processors.
If you are building an embedded Linux system and you find that
glibc is eating up too much space, you should consider using
uClibc. If you are building a huge fileserver with 12 Terabytes
of storage, than using glibc may be a better choice...
uClibc is maintained by Erik Andersen and is licensed under the
GNU LIBRARY GENERAL PUBLIC LICENSE . This license allows you to
make closed source commercial applications using uClibc (Please
consider sharing some of the money you make ;-). You do not need
to give away all your source code just because you use uClibc
and/or run on Linux.
For installation instructions, see the file INSTALL.
This distribution contains a wrapper for gcc and ld that allows you
to use existing toolchains that were targetted for glibc. See
extra/gcc-uClibc/ for information.
uClibc strives to be standards compliant, which means that most
documentation written for functions in glibc also apply to uClibc
functions. However, many GNU extensions are not supported because
they have not been ported, or more importantly, would increase the
size of uClibc disproportional to the added functionality.
Additional information (recent releases, FAQ, mailing list, bugs,
etc.) can be found at http://www.uclibc.org/.
uClibc may be freely modified distributed under the terms of the
GNU Library General Public License, which can be found in the
There is an unwholesomely huge amount of code out there
that depends on the presence of GNU libc header files.
We have GNU libc header files. So we have committed a
horrible sin in uClibc. We _lie_ and claim to be GNU
libc in order to force these applications to work as their
developers intended. This is IMHO, pardonable, since
these defines are not really intended to check for the
presence of a particular library, but rather are used to
define an _interface_. Some programs (such as GNU
binutils) are especially chummy with glibc, and need this
behavior disabled by adding CFLAGS+=__FORCE_NOGLIBC