µ C l i b c

uClibc -- a C library for embedded systems

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, cris, 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, then using glibc may make more sense. Unless, for example, that 12 Terabytes will be Network Attached Storage and you plan to burn Linux into the system's firmware...

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.

### Mailing List Information

uClibc has a mailing list.
To subscribe, go and visit this page.

### Frequently Asked Questions

Before asking questions on the uClibc mailing list, you might want to take a look at the list of Frequently Asked Questions or you might want to search the mailing list archives... ...

### Working Applications List

These days, pretty much everything compiles with uClibc. This is a list of applications that are known to work just fine with uClibc. Since most applications work just fine with uClibc, we are especially interested in knowing about any applications that either do not compile or do not work properly with uClibc. Submissions are welcome!

Latest News

- 9 September 2003, uClibc 0.9.21 Released
  CodePoet Consulting is pleased to announce the immediate availability of uClibc 0.9.21. This release has been brewing for several months now, and provides quite a lot of additional functionality and quite a few bug fixes as well. Many people will be pleased that this release fixes the "dlopen()'ing libraries that depend on libraries" problem.

  The biggest thing in this release (and I do mean that literally) is that uClibc now has full ANSI/ISO C99 locale support. Well, except for wcsftime() and collating items in regex, which are not done yet. Adding support for the default set of locales (169 UTF-8 locales and 144 locales using other codesets) will enlarge uClibc by around 300k. Still, if you need locale support, that is still much better than the roughly 30MB the comparable set of locale date occupies with glibc. And you can of course reduce the 300k by reducing the number of supported locales.

  As usual, this release has many improvements, both large and small. At this point, most applications that compile and work with glibc will also compile and run with uClibc. Both Perl and Python pass all the tests in their test suites (both with and without locale support enabled). We invite you to grab a copy of the latest Linux Test Project test suite and give uClibc some abuse. We are not yet perfect, but we are getting pretty darn close.

  This release is not binary compatible with earlier releases. Depending on your configuration, you may actually still be binary compatible, but it would be a good idea to recompile your applications when moving to the uClibc 0.9.21 release. We are sorry about that, but we have never promised to provide binary compatibility until we hit version 1.0. And even then, if you change your uClibc configuration, you still still generally need to recompile...

  As usual, the Changelog, detailed changelog, and source code for this release are available here.

  Updated uClibc development systems using uClibc 0.9.21 will be made available within a few days.

- Old News
  Click here to read older news.

Sponsors

Please visit our sponsors and thank them for their support! They have provided money, equipment, bandwidth, etc. Next time you need help with a project, consider these fine companies! Several individuals have also contributed (If you have contributed and would like your name added here, just email Erik and let him know).

- Penguru Consulting
  Custom development for embedded Linux systems and multimedia platforms
- opensource.se
  Embedded open source consulting in Europe.
- Codepoet Consulting
  Custom Linux, embedded Linux, BusyBox, and uClibc development.

Do you like uClibc? Do you need support? Do you need some features added? Then why not help out? We are happy to accept donations (such as bandwidth, mirrors sites, and hardware for the various architectures). We can also provide support contracts, and implement funded feature requests. To contribute, you can either click on the Donate image to donate using PayPal, or you can contact Erik at CodePoet Consulting (we have a credit card machine so you can avoid PayPal if you wish).

Download

- Source for the latest release can always be downloaded from http://www.uclibc.org/downloads
- You may want to download uClibc from the closest kernel.org mirror site. Just pick the closest mirror site, and then go to the /pub/linux/libs/uclibc/ directory to download uClibc.
- A daily snapshot of the source is available for those wishing to follow uClibc developments, but cannot or do not wish to use CVS.
- uClibc has a publically browsable CVS tree.
- Anonymous CVS access is available to let you track development.
- CVS write access is also available for those that are actively contributing.

Toolchains

- Steven J. Hill has kindly provided RPMs and SRPMs with toolchains for mips.
- You can build your own uClibc toolchain using these Makefiles which automagically download all the source needed code and compile it for you.
- uClibc development systems for i386 and powerpc, and arm are available and contain complete gcc 3.2.2 toolchains.
- You can compile your own uClibc development system using buildroot.

Other Open Source C libraries:

I am currently aware of the following open source C libraries.

- GNU C Library (aka glibc)
- Al's FREE C Runtime Library
- diet libc
- the minix C library
- newlib
- and there is a C library, for eCos as well.

Links to other useful stuff

- The uClibc home page

- The uClibc CVS tree

- BusyBox

- udhcp

- Embedded Linux Developer Forum

- CodePoet Consulting

Mail all comments, insults, suggestions and bribes to Erik Andersen |  |  |  |  |