C Language
Copyright © 1998 The Open Group


Product Standard
Operating System and Languages: C Language
Document Number: X98LL


©January 1998, The Open Group All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owners.


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Product Standard

NAME

C Language

LABEL FOR LOGO

No label.

DESCRIPTION

ISO C and X/Open Common Usage C Language definitions. Common Usage C is retained for compatibility with XPG3 applications. ISO C is replacing Common Usage C over time.

CONFORMANCE REQUIREMENTS
Human-Computer Interface

Not applicable.

Portability Interface

X/Open Common Usage C, defined in Programming Languages, Issue 31, Chapters 1 to 4, C Language.

ISO C, defined in ISO/IEC 9899:1990 (C Language).2

Programming Language Environment

Not applicable.

The referenced specifications define the ISO C and X/Open Common Usage C dialects.

Interoperability
OPERATIONAL ENVIRONMENT

Not applicable.

PORTABILITY ENVIRONMENT

XPG3 Internationalized System Calls and Libraries, Internationalized System Calls and Libraries, Internationalized System Calls and Libraries Extended, or Internationalized System Calls and Libraries Extended V2.

OVERRIDING STANDARDS

The X/Open specification of ISO C is a direct reference to ISO/IEC 9899:1990 (C Language). Deference is therefore not applicable. X/Open Common Usage C does not defer to any formal standard.

INDICATORS OF COMPLIANCE

Support for both ISO C and Common Usage C is a mandatory requirement for conformance to this Product Standard, and there are separate Indicators of Compliance for each of these language dialects as defined below:

MIGRATION

For a description of the migration path to ISO C, refer to the generally available literature.


Any comments relating to the material contained in this document may be submitted to The Open Group at:

The Open Group
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Reading
Berkshire, RG1 1AX
United Kingdom
or by electronic mail to:
OGSpecs@opengroup.org


Footnotes

1.
X/Open Specification, 1988, 1989, February 1992, Programming Languages, Issue 3 (ISBN: 1-872630-39-1, C214); this specification was formerly X/Open Portability Guide, Volume 4, August 1988 (ISBN: 0-13-685868-6, XO/XPG/89/004).

2.
ISO/IEC 9899:1990, Programming Languages - C (technically identical to ANSI standard X3.159-1989).