Rich Felker
a6244de1c9
v4-compatible addresses in ipv6 are a deprecated feature where the high 96 bits are all zero and an ipv4 address is stored in the low 32 bits. however, since :: and ::1 are the unspecified and loopback addresses, these two particular values are excluded from the definition of the v4-compat class. our version of the macro incorrectly assessed this condition by checking only the high 96 and low 8 bits. this incorrectly excluded the v4compat version of any ipv4 address ending in .1, not just ::1. rather than writing out non-obvious or error-prone conditions on the individual address bytes, just express the "not :: or ::1" condition naturally using the existing IN6_IS_ADDR_UNSPECIFIED and IN6_IS_ADDR_LOOPBACK macros, after checking that the high 96 bits are all zero. any vaguely reasonable compiler will collapse out the redundant tests of the upper bits as part of CSE.
musl libc
musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.
The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.
For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/