README 3.1 KB

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  1. uClibc - a Small C Library for Linux
  2. Erik Andersen <andersen@codepoet.org>
  3. uClibc (aka µClibc/pronounced yew-see-lib-see) is a C library for
  4. developing embedded Linux systems. It is much smaller than the
  5. GNU C Library, but nearly all applications supported by glibc
  6. also work perfectly with uClibc. Porting applications from glibc
  7. to uClibc typically involves just recompiling the source code.
  8. uClibc even supports shared libraries and threading. It currently
  9. runs on standard Linux and MMU-less (also known as µClinux)
  10. systems with support for alpha, ARM, cris, e1, h8300, i386, i960,
  11. m68k, microblaze, mips/mipsel, PowerPC, SH, SPARC, and v850
  12. processors.
  13. If you are building an embedded Linux system and you find that
  14. glibc is eating up too much space, you should consider using
  15. uClibc. If you are building a huge fileserver with 12 Terabytes
  16. of storage, then using glibc may make more sense. Unless, for
  17. example, that 12 Terabytes will be Network Attached Storage and
  18. you plan to burn Linux into the system's firmware...
  19. uClibc is maintained by Erik Andersen and is licensed under the
  20. GNU LIBRARY GENERAL PUBLIC LICENSE . This license allows you to
  21. make closed source commercial applications using an unmodified
  22. version of uClibc (Please consider sharing some of the money you
  23. make ;-). You do not need to give away all your source code just
  24. because you use uClibc and/or run on Linux. You should, however,
  25. carefuly review the license and make certain you understand and
  26. abide by it strictly.
  27. For installation instructions, see the file INSTALL.
  28. uClibc strives to be standards compliant, which means that most
  29. documentation written for SuSv3, or for glibc also applies to
  30. uClibc functions. However, many GNU extensions are not supported
  31. because they have not been ported, or more importantly, would
  32. increase the size of uClibc disproportional to the added
  33. functionality. There is some discussion of these differences
  34. in the "docs" directory.
  35. Additional information (recent releases, FAQ, mailing list, bugs,
  36. etc.) can be found at http://www.uclibc.org/.
  37. uClibc may be freely modified and distributed under the terms of
  38. the GNU Library General Public License, which can be found in the
  39. file COPYING.LIB.
  40. Please Note:
  41. There is an unwholesomely huge amount of code out there
  42. that depends on the presence of GNU libc header files.
  43. We have GNU libc compatible header files. So we have
  44. committed a horrible sin in uClibc. We _lie_ and claim
  45. to be GNU libc in order to force these applications to
  46. work as their developers intended. This is IMHO,
  47. pardonable, since these defines are not really intended
  48. to check for the presence of a particular library, but
  49. rather are used to define an _interface_. Some programs
  50. are especially chummy with glibc, and may need this
  51. behavior disabled by adding CFLAGS+=-D__FORCE_NOGLIBC
  52. If you want to make special exceptions in your code which are
  53. specifically for uClibc, you can make certain to include features.h,
  54. and then have your code check for uClibc as follows:
  55. #ifdef __UCLIBC__
  56. do_something_special();
  57. #endif
  58. And most of all, but sure to have some fun!
  59. -Erik