Erik Andersen <andersen@codepoet.org>
uClibc (aka µClibc/pronounced yew-see-lib-see) is a C library for
-developing embedded Linux systems. It is much smaller than the
+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
+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
+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.
+systems with support for alpha, ARM, cris, e1, h8300, i386, i960,
+m68k, microblaze, 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. 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.
+GNU LESSER GENERAL PUBLIC LICENSE. This license allows you to
+make closed source commercial applications using an unmodified
+version of 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. You should, however,
+carefuly review the license and make certain you understand and
+abide by it strictly.
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.
+documentation written for SuSv3, or for glibc also applies 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. There is some discussion of these differences
+in the "docs" directory.
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
+uClibc may be freely modified and distributed under the terms of
+the GNU Lesser General Public License, which can be found in the
file COPYING.LIB.
Please Note:
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
+ We have GNU libc compatible 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
+ are especially chummy with glibc, and may need this
+ behavior disabled by adding CFLAGS+=-D__FORCE_NOGLIBC
+
+ If you want to make special exceptions in your code which are
+ specifically for uClibc, you can make certain to include features.h,
+ and then have your code check for uClibc as follows:
+
+ #ifdef __UCLIBC__
+ do_something_special();
+ #endif
+And most of all, be sure to have some fun! :-)
+ -Erik
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