1.2.2 POSIX (The Portable Operating System Interface)
The GNU library is also compatible with the ISO POSIX family of
standards, known more formally as the Portable Operating System
Interface for Computer Environments (ISO/IEC 9945). They were also
published as ANSI/IEEE Std 1003. POSIX is derived mostly from various
versions of the Unix operating system.
The library facilities specified by the POSIX standards are a superset
of those required by ISO C; POSIX specifies additional features for
ISO C functions, as well as specifying new additional functions. In
general, the additional requirements and functionality defined by the
POSIX standards are aimed at providing lower-level support for a
particular kind of operating system environment, rather than general
programming language support which can run in many diverse operating
The GNU C library implements all of the functions specified in
ISO/IEC 9945-1:1996, the POSIX System Application Program
Interface, commonly referred to as POSIX.1. The primary extensions to
the ISO C facilities specified by this standard include file system
interface primitives (see File System Interface), device-specific
terminal control functions (see Low-Level Terminal Interface), and
process control functions (see Processes).
Some facilities from ISO/IEC 9945-2:1993, the POSIX Shell and
Utilities standard (POSIX.2) are also implemented in the GNU library.
These include utilities for dealing with regular expressions and other
pattern matching facilities (see Pattern Matching).
Published under the terms of the GNU General Public License