©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

• Data Interchange Formats

  None.
  

• Communications Interfaces and Protocols

  None.

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:

• ISO C

  Any of the following:

  • Current NIST certificate of ANSI/ISO C-language validation.

  • Current entry in the NIST register of validated language processors for ANSI/ISO C Language indicating no non-conformities.

  • Current Certificate of ANSI/ISO C-language validation issued by a member of the GLATC European testing agreement group registered under ECITC.

  • A Test Report from a currently authorized release of either the Perennial ANSI C Validation Suite or the Plum-Hall C Validation Suite, together with the checklist of Implementation-defined Features.

• Common Usage C

  A Test Report from a currently authorized release of the VSX C Language test suite.

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
Apex Plaza
Forbury Road
Reading
Berkshire, RG1 1AX
United Kingdom

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).