BS PD ISO IEC TS 18822-2015 Programming languages C++ File System Technical Specification《编程语言 C++ 文件系统技术规格》.pdf

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1、BSI Standards Publication PD ISO/IEC TS 18822:2015 Programming languages C+ File System Technical SpecificationPD ISO/IEC TS 18822:2015 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of ISO/IEC TS 18822:2015. The UK participation in its preparation was entruste

2、d to Technical Committee IST/5, Programming languages, their environments and system software interfaces. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users

3、are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 84760 8 ICS 35.060 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority o

4、f the Standards Policy and Strategy Committee on 30 June 2015. Amendments/corrigenda issued since publication Date T e x t a f f e c t e dReference number ISO/IEC TS 18822:2015(E) ISO/IEC 2015 TECHNICAL SPECIFICATION ISO/IEC TS 18822 First edition 2015- 0 7 - 0 1 Programming languages C+ File System

5、 Technical Specification Languages de programmation C+ Spcification technique de systme de fichiers PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E) COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized o

6、therwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright off

7、ice Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO/IEC 2015 All rights reservedPD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E) ISO/IEC 2015 All rights reserved iiiForeword ISO (the International

8、 Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by t

9、he respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of i

10、nformation technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft Intern

11、ational Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement

12、for such documents, the joint technical committee may decide to publish other types of document: an ISO/IEC Publicly Available Specification (ISO/IEC PAS) represents an agreement between technical experts in an ISO/IEC working group and is accepted for publication if it is approved by more than 50 %

13、 of the members of the parent committee casting a vote; an ISO/IEC Technical Specification (ISO/IEC TS) represents an agreement between the members of the joint technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/IEC PAS

14、 or ISO/IEC TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/IEC PAS or ISO/IEC TS is confirmed, it is reviewed again after a further three years, at which time it must ei

15、ther be transformed into an International Standard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC TS 18822 was prep

16、ared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 22, Programming languages, their environments and system software interfaces. PD ISO/IEC TS 18822:2015 Contents Contents 1 Scope 2 Conformance 2.1 POSIX conformance 2.2 Operating system dependent behavior confor

17、mance 2.3 File system race behavior 3 Normative references 4 Terms and definitions 4.1 absolute path 4.2 canonical path 4.3 directory 4.4 file 4.5 file system 4.6 file system race 4.7 filename 4.8 hard link 4.9 link 4.10 native encoding 4.11 native pathname format 4.12 NTCTS 4.13 operating system de

18、pendent behavior 4.14 parent directory 4.15 path 4.16 pathname 4.17 pathname resolution 4.18 relative path 4.19 symbolic link 5 Requirements 5.1 Namespaces and headers 5.2 Feature test macros 6 Header synopsis 7 Error reporting 8 Classpath 8.1path generic pathname format grammar 8.2path conversions

19、8.2.1path argument format conversions 8.2.2path type and encoding conversions 8.3path requirements 8.4path members 8.4.1path constructors 8.4.2path assignments ISO/IEC N4100 iii PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 8.4.3path appends 8.4.4path concatenation 8.4.5p

20、ath modifiers 8.4.6path native format observers 8.4.7path generic format observers 8.4.8path compare 8.4.9path decomposition 8.4.10path query 8.5path iterators 8.6path non-member functions 8.6.1path inserter and extractor 8.6.2path factory functions 9 Classfilesystem_error 9.1filesystem_error member

21、s 10 Enumerations 10.1 Enum classfile_type 10.2 Enum classcopy_options 10.3 Enum classperms 10.4 Enum classdirectory_options 11 Classfile_status 11.1file_status constructors 11.2file_status observers 11.3file_status modifiers 12 Classdirectory_entry 12.1directory_entry constructors 12.2directory_ent

22、ry modifiers 12.3directory_entry observers 13 Classdirectory_iterator 13.1directory_iterator members 13.2directory_iterator non-member functions 14 Classrecursive_directory_iterator 14.1recursive_directory_iterator members 14.2recursive_directory_iterator non-member functions 15 Operational function

23、s 15.1 Absolute 15.2 Canonical 15.3 Copy 15.4 Copy file 15.5 Copy symlink 15.6 Create directories 15.7 Create directory 15.8 Create directory symlink 15.9 Create hard link 15.10 Create symlink ISO/IEC N4100 iv PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 15.11 Current pa

24、th 15.12 Exists 15.13 Equivalent 15.14 File size 15.15 Hard link count 15.16 Is block file 15.17 Is character file 15.18 Is directory 15.19 Is empty 15.20 Is fifo 15.21 Is other 15.22 Is regular file 15.23 Is socket 15.24 Is symlink 15.25 Last write time 15.26 Permissions 15.27 Read symlink 15.28 Re

25、move 15.29 Remove all 15.30 Rename 15.31 Resize file 15.32 Space 15.33 Status 15.34 Status known 15.35 Symlink status 15.36 System complete 15.37 Temporary directory path ISO/IEC N4100 v PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 1 Scope fs.scope 1 This Technical Speci

26、fication specifies requirements for implementations of an interface that computer programs written in the C+ programming language may use to perform operations on file systems and their components, such as paths, regular files, and directories. This Technical Specification is applicable to informati

27、on technology systems that can access hierarchical file systems, such as those with operating systems that conform to the POSIX (3) interface. This Technical Specification is applicable only to vendors who wish to provide the interface it describes. 2 Conformance fs.conformance 1 Conformance is spec

28、ified in terms of behavior. Ideal behavior is not always implementable, so the conformance sub-clauses take that into account. 2.1 POSIX conformance fs.conform.9945 1 Some behavior is specified by reference to POSIX (3). How such behavior is actually implemented is unspecified. 2 Note: This constitu

29、tes an “as if“ rule allowing implementations to call native operating system or other APIs. end note 3 Implementations are encouraged to provide such behavior as it is defined by POSIX. Implementations shall document any behavior that differs from the behavior defined by POSIX. Implementations that

30、do not support exact POSIX behavior are encouraged to provide behavior as close to POSIX behavior as is reasonable given the limitations of actual operating systems and file systems. If an implementation cannot provide any reasonable behavior, the implementation shall report an error as specified in

31、 7. 4 Note: This allows users to rely on an exception being thrown or an error code being set when an implementation cannot provide any reasonable behavior. end note 5 Implementations are not required to provide behavior that is not supported by a particular file system. 6 Example: The FAT file syst

32、em used by some memory cards, camera memory, and floppy discs does not support hard links, symlinks, and many other features of more capable file systems, so implementations are not required to support those features on the FAT file system. end example 2.2 Operating system dependent behavior conform

33、ance fs.conform.os 1 Some behavior is specified as being operating system dependent (4.13). The operating system an implementation is dependent upon is implementation defined. ISO/IEC N4100 1 PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 2 It is permissible for an impleme

34、ntation to be dependent upon an operating system emulator rather than the actual underlying operating system. 2.3 File system race behavior fs.race.behavior 1 Behavior is undefined if calls to functions provided by this Technical Specification introduce a file system race (4.6). 2 If the possibility

35、 of a file system race would make it unreliable for a program to test for a precondition before calling a function described herein, Requires is not specified for the function. 3 Note: As a design practice, preconditions are not specified when it is unreasonable for a program to detect them prior to

36、 calling the function. end note 3 Normative references fs.norm.ref 1 The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any a

37、mendments) applies. 2 ISO/IEC 14882, Programming Language C+ 3 ISO/IEC 9945, Information Technology Portable Operating System Interface (POSIX) 4 Note: The programming language and library described in ISO/IEC 14882 is herein called the C+ Standard. References to clauses within the C+ Standard are w

38、ritten as “C+14 3.2“. Section references are relative to N3936. 5 The operating system interface described in ISO/IEC 9945 is herein called POSIX. end note 6 This Technical Specification mentions commercially available operating systems for purposes of exposition. footnote 7 Unless otherwise specifi

39、ed, the whole of the C+ Standards Library introduction (C+14 17) is included into this Technical Specification by reference. 8 footnote POSIX is a registered trademark of The IEEE. MAC OS is a registered trademark of Apple Inc. Windows is a registered trademark of Microsoft Corporation. This informa

40、tion is given for the convenience of users of this document and does not constitute an endorsement by ISO or IEC of these products. ISO/IEC N4100 2 PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 4 Terms and definitions fs.definitions 1 For the purposes of this document, th

41、e terms and definitions given in the C+ Standard and the following apply. 4.1 absolute path fs.def.absolute-path 1 A path that unambiguously identifies the location of a file without reference to an additional starting location. The elements of a path that determine if it is absolute are operating s

42、ystem dependent. 4.2 canonical path fs.def.canonical-path 1 An absolute path that has no elements that are symbolic links, and no dot or dot-dot elements (8.1). 4.3 directory fs.def.directory 1 A file within a file system that acts as a container of directory entries that contain information about o

43、ther files, possibly including other directory files. 4.4 file fs.def.file 1 An object within a file system that holds user or system data. Files can be written to, or read from, or both. A file has certain attributes, including type. File types include regular files and directories. Other types of

44、files, such as symbolic links, may be supported by the implementation. 4.5 file system fs.def.filesystem 1 A collection of files and certain of their attributes. 4.6 file system race fs.def.race 1 The condition that occurs when multiple threads, processes, or computers interleave access and modifica

45、tion of the same object within a file system. 4.7 filename fs.def.filename 1 The name of a file. Filenames dot and dot-dot have special meaning. The following characteristics of filenames are operating system dependent: 2 The permitted characters. Example: Some operating systems prohibit the ASCII c

46、ontrol characters (0x00-0x1F) in filenames. end example. 3 The maximum permitted length. 4 Filenames that are not permitted. ISO/IEC N4100 3 PD ISO/IEC TS 18822:2015 ISO/IEC TS 18822:2015(E)PD ISO/IEC TS 18822:2015 5 Filenames that have special meaning. 6 Case awareness and sensitivity during path r

47、esolution. 7 Special rules that may apply to file types other than regular files, such as directories. 4.8 hard link fs.def.hardlink 1 A link (4.9) to an existing file. Some file systems support multiple hard links to a file. If the last hard link to a file is removed, the file itself is removed. 2

48、Note: A hard link can be thought of as a shared-ownership smart pointer to a file. end note 4.9 link fs.def.link 1 A directory entry that associates a filename with a file. A link is either a hard link (4.8) or a symbolic link (4.19). 4.10 native encoding fs.def.native.encode 1 For narrow character

49、strings, the operating system dependent current encoding for path names. For wide character strings, the implementation defined execution wide-character set encoding (C+14 2.3). 4.11 native pathname format fs.def.native 1 The operating system dependent pathname format accepted by the host operating system. 4.12 NTCTS fs.def.ntcts 1 Acronym for “null-terminated character-type sequence“. Describes a sequence of values of a given encoded character