Node:Berkeley Unix, Next:SVID, Previous:POSIX, Up:Standards and Portability
The GNU C library defines facilities from some versions of Unix which
are not formally standardized, specifically from the 4.2 BSD, 4.3 BSD,
and 4.4 BSD Unix systems (also known as Berkeley Unix) and from
SunOS (a popular 4.2 BSD derivative that includes some Unix System
V functionality). These systems support most of the ISO C and POSIX
facilities, and 4.4 BSD and newer releases of SunOS in fact support them all.
The BSD facilities include symbolic links (see Symbolic Links), the
select
function (see Waiting for I/O), the BSD signal
functions (see BSD Signal Handling), and sockets (see Sockets).