1# bionic documentation
2
3[bionic](https://en.wikipedia.org/wiki/Bionic_(software)) is Android's
4C library, math library, and dynamic linker.
5
6## User documentation
7
8* [Android bionic status](status.md) - where we are in terms of standards,
9  and what changed with each OS release.
10* [32-bit ABI bugs](32-bit-abi.md) - historical accidents we can never fix.
11* [`EINTR`](EINTR.md) - what is the `EINTR` failure,
12  and how can code deal with it?
13* [When to use which `#define`](defines.md) - how to choose between
14  `__ANDROID__` and `__BIONIC__` and all the other options for conditional
15  compilation.
16* [fdsan](fdsan.md) - bionic's file descriptor sanitizer,
17  which detects use-after-close() bugs.
18* [fdtrack](fdtrack.md) - bionic's file descriptor tracker,
19  which helps debug file descriptor leaks.
20
21## Maintainer documentation
22
23If you're trying to make changes to bionic _itself_, start with the
24[bionic maintainer documentation](../README.md).
25
26We also have more detail on several specific parts of the implementation:
27
28* [The anatomy of bionic's `_FORTIFY_SOURCE`](clang_fortify_anatomy.md) -
29  how does `_FORTIFY_SOURCE` work on bionic (primarily "with clang").
30* [Android ELF TLS](elf-tls.md) - details of bionic's ELF TLS implementation.
31* [Validating libc assembler](libc_assembler.md) - how to test changes to
32  libc assembler routines.
33* [Validating native allocator changes](native_allocator.md) - how to test
34  changes to the native allocator.
35