bionic/libc
Elliott Hughes a985076bfe Fix sysconf(_SC_NPROCESSORS_CONF) on ARM.
Bug: http://code.google.com/p/enh/issues/detail?id=33
Change-Id: I679b4cd888d362031042284e8edf01c5273a92aa
2012-06-06 12:04:38 -07:00
..
arch-arm Add linker support for PIE 2012-05-15 09:56:32 -07:00
arch-mips [MIPS] Add support for MIPS syscalls 2012-05-09 11:46:28 -07:00
arch-x86 bionic/x86: Optimization for memcpy 2012-05-08 12:18:25 -07:00
bionic Give the timer_create SIGEV_THREAD helper threads sensible names. 2012-06-06 10:32:56 -07:00
docs libc: Fix the definition of SIGRTMAX 2010-12-20 15:58:06 +01:00
include Actually set the header guard in "linux-syscalls.h". 2012-05-09 16:34:11 -07:00
inet Fix build. 2011-06-09 13:03:17 -07:00
kernel bionic: add clean kernel header ucontext.h 2012-05-14 01:42:12 +08:00
netbsd Merge "Remove expired dns cache entries before removing oldest" 2012-05-07 10:41:53 -07:00
private bionic: Fix wrong kernel_id in pthread descriptor after fork() 2012-03-12 23:14:56 +08:00
regex Remove compiler warnings when building Bionic. 2010-06-22 17:51:41 -07:00
stdio am 4685acbd: am 9efda5b7: Merge "typo in libc/stdio/wcio.h" 2011-08-03 08:16:37 -07:00
stdlib Enable functional DSO object destruction 2011-07-07 22:51:43 +02:00
string string: Fix wrong comparison semantics 2011-12-05 18:37:10 -08:00
tools Remove the last references to SuperH. 2012-05-15 17:08:41 -07:00
tzcode am ac56f5ca: Merge "strftime: Use snprintf() instead of sprintf()" 2011-06-23 06:13:53 -07:00
unistd Fix sysconf(_SC_NPROCESSORS_CONF) on ARM. 2012-06-06 12:04:38 -07:00
wchar wchar.h: improve wchar_t support in Bionic 2010-06-15 07:04:41 -07:00
zoneinfo Update to tzdata2012c. 2012-04-02 07:43:15 -07:00
Android.mk Give the timer_create SIGEV_THREAD helper threads sensible names. 2012-06-06 10:32:56 -07:00
CAVEATS auto import from //depot/cupcake/@135843 2009-03-03 19:28:35 -08:00
Jamfile 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 Clean up NOTICE files. 2010-10-19 15:12:40 -07:00
README Add an 's and a . to the bionic/libc README. 2009-07-23 17:41:47 -07:00
SYSCALLS.TXT [MIPS] Add support for MIPS syscalls 2012-05-09 11:46:28 -07:00

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.