bionic/libc
Elliott Hughes 76be660aae Clean up libc/Android.mk a bit after the crtbrand changes.
Change-Id: Icfb95fffe70967418cd93da8cbeae22dcd68f8c9
2012-08-08 14:07:37 -07:00
..
arch-arm bionic: Stack pointer/signal race condition. 2012-07-27 15:11:01 +02:00
arch-mips MIPS support for libc. 2012-08-02 16:07:26 -07:00
arch-x86 Merge "Remove an awkward #include that is no longer upstream." 2012-08-06 07:57:59 -07:00
bionic Merge "Add a .note.android.ident section to Android ELF binaries." 2012-08-08 13:44:27 -07:00
docs libc: Fix the definition of SIGRTMAX 2010-12-20 15:58:06 +01:00
include Merge "When compiling with clang, don't "fortify_source" the strlcpy and strlcat." 2012-08-06 11:02:19 -07:00
inet inet_ntop: pass the size of tmp to snprintf() 2012-06-11 16:00:52 -07:00
kernel Updated the cleaned header file mman.h for MIPS. 2012-07-31 14:47:51 -07:00
netbsd am c5cab345: am 028ccf5d: Merge "Avoid multiple dns lookups for the same query" 2012-06-12 15:56:29 -07:00
private [MIPS] Support for TLS register 2012-08-02 18:01:05 -07:00
regex Remove compiler warnings when building Bionic. 2010-06-22 17:51:41 -07:00
stdio vfprintf: fix spelling. 2012-07-25 16:01:38 -07:00
stdlib fix __cxa_finalize() implementation to be thread safe. 2012-07-31 12:30:28 +02:00
string Error numbers are target specific. 2012-08-01 17:53:07 -07:00
tools Remove the 'Factory' time zone by not processing the 'factory' file. 2012-07-26 16:19:46 -07:00
tzcode libc: remove private declarations from <time.h> and <resolv.h> 2012-01-13 14:24:08 +01:00
unistd Report errors to the log, not just stderr. 2012-07-27 17:43:38 -07:00
wchar wchar.h: improve wchar_t support in Bionic 2010-06-15 07:04:41 -07:00
zoneinfo Upgrade to tzdata2012e. 2012-08-03 12:26:06 -07:00
Android.mk Clean up libc/Android.mk a bit after the crtbrand changes. 2012-08-08 14:07:37 -07:00
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 Add a .note.android.ident section to Android ELF binaries. 2012-07-31 16:18:22 +12:00
README Add an 's and a . to the bionic/libc README. 2009-07-23 17:41:47 -07:00
SYSCALLS.TXT resolved conflicts for merge of e5408907 to jb-dev-plus-aosp 2012-05-09 13:53:37 -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.