.. comment SPDX-License-Identifier: CC-BY-SA-4.0 ======= Preface ======= This document lists the functions, constant, macros, feature flags, and types defined in the POSIX 1003.1 standard. Each section in this document corresponds to a section in the 1003.1 standard and the implementation status of the items required by the standard are listed. RTEMS supports a number of POSIX process, user, and group oriented routines in what is referred to as a "SUSP" (Single-User, Single Process) manner. RTEMS supports a single process, multithreaded POSIX 1003.1b environment. In a pure world, there would be no reason to even include routines like ``getpid()`` when there can only be one process. But providing routines like ``getpid()`` and making them work in a sensible fashion for an embedded environment while not returning ENOSYS (for not implemented) makes it significantly easier to port code from a UNIX environment without modifying it. .. COMMENT: COPYRIGHT (c) 1988-2002. .. COMMENT: On-Line Applications Research Corporation (OAR). .. COMMENT: All rights reserved.