bionic/libc
Elliott Hughes 7e29f81163 am 4ff6fa97: am 2bbb8fac: Merge "Add signalfd call to bionic"
* commit '4ff6fa97e7cf247e17600cf0d64911c1579df841':
  Add signalfd call to bionic
2013-01-11 10:54:02 -08:00
..
arch-arm Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
arch-mips Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
arch-x86 Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
bionic Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
docs Remove obsolete CHANGES.TXT and ISSUES.TXT. 2012-10-17 11:33:59 -07:00
include Add signalfd call to bionic 2013-01-10 13:14:46 -08:00
kernel am 2bbb8fac: Merge "Add signalfd call to bionic" 2013-01-10 13:30:16 -08:00
netbsd Cache negative DNS results. 2013-01-09 16:36:33 -08:00
private am 8717c3db: am 7a34ed2b: Merge "clean up FORTIFY_SOURCE handling." 2012-12-05 08:25:37 -08:00
stdio Define DEFFILEMODE and friends 2012-11-29 11:53:33 -08:00
stdlib More upstream NetBSD upgrades. 2012-10-23 16:05:09 -07:00
string clean up FORTIFY_SOURCE handling. 2012-12-04 15:27:30 -08:00
tools Verify architecture neutral syscall numbers 2012-11-29 12:04:23 -08:00
tzcode am 85819efe: am f2b3ac95: Merge "Fix recovery: don\'t assert if there\'s no tzdata." 2012-10-25 15:16:44 -07:00
unistd More upstream NetBSD upgrades. 2012-10-23 16:05:09 -07:00
upstream-dlmalloc Fix build warning of initialization but no use. 2012-09-06 09:59:13 -07:00
upstream-netbsd libc: Fix alphasort() signature (and implementation). 2012-10-29 07:44:27 -07:00
wchar Move non-upstream code into the libc/bionic directory. 2012-10-01 17:35:49 -07:00
zoneinfo Upgrade to tzdata2012j. 2012-11-26 14:51:39 -08:00
Android.mk am 4ff6fa97: am 2bbb8fac: Merge "Add signalfd call to bionic" 2013-01-11 10:54:02 -08:00
CAVEATS auto import from //depot/cupcake/@135843 2009-03-03 19:28:35 -08:00
MODULE_LICENSE_BSD auto import from //depot/cupcake/@135843 2009-03-03 19:28:35 -08:00
NOTICE Update generate-NOTICE.py to know about tzdata. 2012-10-19 14:55:19 -07:00
README Add an 's and a . to the bionic/libc README. 2009-07-23 17:41:47 -07:00
SYSCALLS.TXT Add signalfd call to bionic 2013-01-10 13:14:46 -08:00

Welcome to Bionic, Android's small and custom C library for the Android
platform.

Bionic is mainly a port of the BSD C library to our Linux kernel with the
following additions/changes:

- no support for locales
- no support for wide chars (i.e. multi-byte characters)
- its own smallish implementation of pthreads based on Linux futexes
- support for x86, ARM and ARM thumb CPU instruction sets and kernel interfaces

Bionic is released under the standard 3-clause BSD License

Bionic doesn't want to implement all features of a traditional C library, we only
add features to it as we need them, and we try to keep things as simple and small
as possible. Our goal is not to support scaling to thousands of concurrent threads
on multi-processors machines; we're running this on cell-phones, damnit !!

Note that Bionic doesn't provide a libthread_db or a libm implementation.


Adding new syscalls:
====================

Bionic provides the gensyscalls.py Python script to automatically generate syscall
stubs from the list defined in the file SYSCALLS.TXT. You can thus add a new syscall
by doing the following:

- edit SYSCALLS.TXT
- add a new line describing your syscall, it should look like:

   return_type  syscall_name(parameters)    syscall_number

- in the event where you want to differentiate the syscall function from its entry name,
  use the alternate:

   return_type  funcname:syscall_name(parameters)  syscall_number

- additionally, if the syscall number is different between ARM and x86, use:

   return_type  funcname[:syscall_name](parameters)   arm_number,x86_number

- a syscall number can be -1 to indicate that the syscall is not implemented on
  a given platform, for example:

   void   __set_tls(void*)   arm_number,-1


the comments in SYSCALLS.TXT contain more information about the line format

You can also use the 'checksyscalls.py' script to check that all the syscall
numbers you entered are correct. It does so by looking at the values defined in
your Linux kernel headers. The script indicates where the values are incorrect
and what is expected instead.