ISO/IEC TS 6010

Programming languages — C — A provenance-aware memory object model for C

Langages de programmation — C — Modèle d’objet mémoire sensible à la provenance pour C

General Information

• Status: Not Published
• ICS: 35.060 - Languages used in information technology
• Technical Committee: ISO/IEC JTC 1/SC 22 - Programming languages, their environments and system software interfaces
• Drafting Committee: ISO/IEC JTC 1/SC 22 - Programming languages, their environments and system software interfaces
• Current Stage: 6000 - International Standard under publication
• Due Date: 11-Feb-2025
• Completion Date: 11-Feb-2025

Standards Content (Sample)

FINAL DRAFT
Technical
Specification
ISO/IEC DTS 6010
ISO/IEC JTC 1/SC 22
Programming languages — C — A
Secretariat: ANSI
provenance-aware memory object
Voting begins on:
model for C
2024-12-16
Voting terminates on:
2025-02-10
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
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INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/IEC DTS 6010:2024(en) © ISO/IEC 2024

FINAL DRAFT
ISO/IEC DTS 6010:2024(en)
Technical
Specification
ISO/IEC DTS 6010
ISO/IEC JTC 1/SC 22
Programming languages — C — A
Secretariat: ANSI
provenance-aware memory object
Voting begins on:
model for C
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO/IEC 2024
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
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Published in Switzerland Reference number
ISO/IEC DTS 6010:2024(en) © ISO/IEC 2024

© ISO/IEC 2024 – All rights reserved
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ISO/DISTS6010(en)
Contents
1 Scope 3
2 Normativereferences 3
3 Termsanddefinitions 3
4 Environment 4
4.1 Executionenvironments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2 Sizesofintegertypes . . . . . . . . . . . . . . . . . . . . . . . 4
5 Language 5
5.1 Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1.1 Storagedurationsandobjectlifetimes . . . . . . . . . . . . . . . . . 5
5.1.2 Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1.3 Representationoftypes . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2 Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2.1 Lvalues,arraysandfunctiondesignators . . . . . . . . . . . . . . . 8
5.2.2 Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2.3 Stringliterals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3 Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3.2 Postfixoperators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3.3 Addressandindirectionoperators . . . . . . . . . . . . . . . . . . . 11
5.3.4 Additiveoperators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3.5 Relationaloperators . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3.6 Equalityoperators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3.7 Assignmentoperators . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3.8 Declarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3.9 Structureandunionspecifiers . . . . . . . . . . . . . . . . . . . . . . 13
5.3.10 Arraydeclarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3.11 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4 Statementsandblocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4.2 Theswitchstatement . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.5 Externaldefinitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.5.2 Functiondefinitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6 Library 14
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6.1 Useoflibraryfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.2 Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.3 Thelongjmpfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.4 Thesignalfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.5 Variablearguments . . . . . . . . . . . . . . . . . . . . . . . . 16
6.6 Atomics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.6.1 TheATOMIC_VAR_INITmacro . . . . . . . . . . . . . . . . . . . . 16
6.6.2 Atomicflagtypeandoperations . . . . . . . . . . . . . . . . . . . . . 16
6.7 Integertypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.7.1 Integertypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.7.2 Macrosforintegerconstants . . . . . . . . . . . . . . . . . . . . . . . 17
6.8 Input/output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.8.1 Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.8.2 Files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.8.3 Fileaccessfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.8.4 Directioninput/outputfunctions . . . . . . . . . . . . . . . . . . . . 18
6.9 Generalutilities . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.9.1 Storagemanagementfunctions . . . . . . . . . . . . . . . . . . . . . 19
6.9.2 Multibyte/widecharacterconversionfunctions. . . . . . . . . . . 20
6.10 Stringhandling . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.10.1 Copyingfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.10.2 Thestrxfrmfunction . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.11 Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.11.1 Thetss_createfunction . . . . . . . . . . . . . . . . . . . . . . . . 20
6.11.2 Thetss_setfunction . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.12 Thestrftimefunction,Dateandtime . . . . . . . . . . . . . 21
6.13 Extendedmultibyteandwidecharacterutilities. . . . . . . 21
6.13.1 Thefwprintffunction. . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.13.2 Thefwscanffunction . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.13.3 Thefgetwsfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.13.4 Thewcsxfrmfunction . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.13.5 Thewcsftimefunction. . . . . . . . . . . . . . . . . . . . . . . . . . 22
AnnexA(informative)Portabilityissues 23
AnnexB(informative)Boundscheckinginterfaces 24
AnnexC(informative)Analyzability 25
Index 26
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ISO/DISTS6010(en)
Foreword
ISO(theInternationalOrganizationforStandardization)andIEC(theInternational
Electrotechnical Commission) form the specialized system for worldwide
standardization. National bodies that are members of ISO or IEC participate in
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approval criteria needed for the different types of document should be noted. This
documentwasdraftedinaccordancewiththeeditorialrulesoftheISO/IECDirectives,
Part2(seewww.iso.org/directivesorwww.iec.ch/members_experts/refdocs).
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ThisdocumentwaspreparedbyJointTechnicalCommitteeISO/IECJTC1,Information
technology, Subcommittee SC 22, Programming languages, their environments and
systemsoftwareinterfaces.
Any feedback or questions on this document should be directed to the user’s
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Introduction
TheresolutionofDR260confirmedtheconceptofprovenanceofpointers,introducedas
meanstotrackanddistinguishpointervaluesthatrepresentstorageinstanceswiththe
sameaddress. Implementationsstartedtousethatconceptinoptimisationsrelyingon
provenance-basedaliasanalysis,withoutiteverbeingclearlyorformallydefined,and
withoutitbeingintegratedconsistentlywiththerestoftheCstandard. Thisdocument
providesasolutionforthis:aprovenance-awarememoryobjectmodelforCtoputC
programmersandimplementersonasolidfootinginthisregard.
In addition to this document, https://cerberus.cl.cam.ac.uk/cerberus provides an
executableversionofthesemantics,withawebinterfacethatallowsonetoexplore
andvisualisethebehaviourofsmalltestprograms.
Thisdocumentdoesnotaddresssubobjectprovenance.
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ISO/DISTS6010(en)
1 Scope
Thisdocumentspecifiestheformandestablishestheinterpretationofprogramswritten
intheCprogramminglanguage. Itisnotacompletespecificationofthatlanguagebut
builds upon ISO/IEC 9899:2018 by constraining and clarifying the Memory Object
Model.
2 Normativereferences
Thefollowingdocumentsarereferredtointhetextinsuchawaythatsomeorallof
theircontentconstitutesrequirementsofthisdocument. Fordatedreferences,only
theeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenced
document(includinganyamendments)applies.
ISO/IEC9899:2018,Programminglanguages–C
ISO80000–2,Quantitiesandunits—Part2: Mathematicalsignsandsymbolsto
beusedinthenaturalsciencesandtechnology.
3 Termsanddefinitions
For the purposes of this document, the terms and definitions given in ISO/IEC
9899:2018andthefollowingapply.
ISOandIECmaintainterminologydatabasesforuseinstandardizationatthefollowing
addresses:
– ISOOnlinebrowsingplatform: availableathttps://www.iso.org/obp/ui
– IECElectropedia: availableathttps://www.electropedia.org/
3.1
pointerprovenance
provenance
entity that is associated to a pointer value in the abstract machine, which is either
empty,ortheidentityofastorageinstance
3.2
storageinstance
storageinstance
inclusion-maximalregionofdatastorageintheexecutionenvironmentthatiscreated
wheneitheranobjectdefinitionoranallocationisencountered
Note1toentry: Storageinstancesarecreatedanddestroyedwhenspecificlanguageconstructs(ISO/IEC
9899:2018,6.2.4)aremetduringprogramexecution,includingprogramstartup,orwhenspecificlibrary
functions(ISO/IEC9899:2018,7.22.3)arecalled.
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ISO/DISTS6010(en)
Note 2 to entry: It is possible that a storage instance does not have a memory address and is not
accessiblefromallthreadsofexecution.
Note3toentry: Storageinstanceshaveidentitieswhichareuniqueacrosstheprogramexecution.
Note4toentry: Astorageinstancewithamemoryaddressoccupiesaregionofzeroormorebytesof
contiguousdatastorageintheexecutionenvironment.
Note5toentry: Oneormoreobjectscanberepresentedwithinthesamestorageinstance,suchas
twosubobjectswithinanobjectofstructuretype,twoconst-qualifiedcompoundliteralswithidentical
objectrepresentation,ortwostringliteralswhereoneistheterminalcharactersequenceoftheother.
3.3
indeterminaterepresentation
object representation that either represents an unspecified value or is a non-value
representation
Note1toentry: Thisitemisadaptedfromtheterm"indeterminatevalue"(ISO/IEC9899:2018,3.19.2)
3.4
unspecifiedvalue
valid value of the relevant type where this document imposes no requirements on
whichvalueischoseninanyinstance
[SOURCE:ISO/IEC9899:2018,3.19.3,modified-Note1toentryhasbeenremoved.]
3.5
non-valuerepresentation
objectrepresentationthatdoesnotrepresentavalueoftheobjecttype
Note 1 to entry: This term was adapted from the term "trap representation" (ISO/IEC 9899:2018,
3.19.4)
4 Environment
4.1 Executionenvironments
The requirements in ISO/IEC 9899:2818, 5.1.2.3 shall apply in addition to the
following. For the purposes of this document, when processing of the abstract
machine is interrupted by the receipt of a signal, the representation of any object
modified by the handler that is neither a lock-free atomic object nor of type
volatile sig_atomic_tbecomesindeterminatewhenthehandlerexits.
4.2 Sizesofintegertypes
TherequirementsinISO/IEC9899:2018,5.2.4.2.1shallapply. Inadditionifthevalue
and promoted type is in the range of the type intmax_t (for a signed type) or
uintmax_t(foranunsignedtype),seeISO/IEC9899:2018,7.20.1.5,theexpression
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shallbesui
...