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This update adds the following: C11 Programming Language Standard FACE Technical Standard Edition 3.0 (four profiles) Software Communication Architecture Specification 2.2.2 (one profile) Software Communication Architecture Specification 4.1 (three profiles)
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.. comment SPDX-License-Identifier: CC-BY-SA-4.0
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.. COMMENT: COPYRIGHT (c) 1988-2017.
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.. COMMENT: On-Line Applications Research Corporation (OAR).
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.. COMMENT: All rights reserved.
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Preface
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=======
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RTEMS supports a variety of POSIX and BSD features including some POSIX
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methods that are now deemed obsolete and some methods for compatibility
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with GNU/Linux and FreeBSD. There are multiple POSIX standard versions
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as well as multiple efforts to tailor (e.g. profile) POSIX for embedded
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environments. They range in size from less than 200 required capabilities
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to the full POSIX standard which has over 1200 required capabilities. This
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document reports on the alignment of RTEMS with various standard versions
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and defined profiles.
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RTEMS supports a number of POSIX process, user, and group oriented
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routines in what is referred to as a "SUSP" (Single-User, Single
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Process) manner. RTEMS supports a single process, multithreaded
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POSIX environment. In a pure world, there would be no reason to even
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include routines like ``getpid()`` when there can only be one process.
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But providing routines like ``getpid()`` and making them work in
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a sensible fashion for an embedded environment while not returning
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``ENOSYS`` (for not implemented) makes it significantly easier to port
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code from a UNIX environment without modifying it.
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In general, adding missing methods is always an open project for a
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volunteer. If considering addressing missing methods, please discuss
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this on mailing list. Some are properly implemented in the Newlib
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C Standard Library used by RTEMS. Others may require target architecture
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specific implementations. Still others may be impossible to implement
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without multiple processes or can only be implemented in a restricted
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fashion.
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Missing methods required by the C99 standard or FACE Technical
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Standard Edition 3.0 General Purpose Profile are good candidates to add.
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Proposals to add missing methods from the C11 standard should be reviewed
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by RTEMS core developers to ensure the effort is well spent. There are
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rumors that some optional methods that are not being widely implemented
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will be removed in a future versino of the C Programming Language standard.
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The next chapter in this document describes each of the standards
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with which the RTEMS alignment is tracked. Each subsequent chapter in
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this document presents the alignment of RTEMS with a specific standard
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version or defined profile. Each section with a chapter details the
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alignment of a specific header file relative to the chapter's standard
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or profile. The implementation status of the items required by the
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standard are listed.
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