Стандарт C++ 98, страница 2

National bodies that are members of ISO or IEC participate in thedevelopment of International Standards through technical committees establishedby the respective organization to deal with particular fields of technical activity.ISO and IEC technical committees collaborate in fields of mutual interest. Otherinternational organizations, governmental and non-governmental, in liaison withISO and IEC, also take part in the work.In the field of information technology, ISO and IEC have established a jointtechnical committee, ISO/IEC JTC 1. Draft International Standards adopted by thejoint technical committee are circulated to national bodies for voting. Publicationas an International Standard requires approval by at least 75 % of the nationalbodies casting a vote.International Standard ISO/IEC 14882 was prepared by Joint TechnicalCommittee ISO/IEC JTC 1, Information technology, Subcommittee SC 22,Programming languages, their environments and system software interfaces.Annexes D and E form an integral part of this International Standard.

Annexes Ato C are for information only.xxvi_______________________________________________________________________________________INTERNATIONAL STANDARD©ISO/IECISO/IEC 14882:1998(E)_______________________________________________________________________________________Programming languages – C++1 General1.1 Scope[intro][intro.scope]1This International Standard specifies requirements for implementations of the C++ programming language.The first such requirement is that they implement the language, and so this International Standard alsodefines C++. Other requirements and relaxations of the first requirement appear at various places withinthis International Standard.2C++ is a general purpose programming language based on the C programming language as described inISO/IEC 9899:1990 Programming languages – C (1.2).

In addition to the facilities provided by C, C++provides additional data types, classes, templates, exceptions, namespaces, inline functions, operator overloading, function name overloading, references, free store management operators, and additional libraryfacilities.1.2 Normative references1[intro.refs]The following standards contain provisions which, through reference in this text, constitute provisions ofthis International Standard.

At the time of publication, the editions indicated were valid. All standards aresubject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IECand ISO maintain registers of currently valid International Standards.— ISO/IEC 2382 (all parts), Information technology – Vocabulary— ISO/IEC 9899:1990, Programming languages – C— ISO/IEC 9899/Amd.1:1995, Programming languages – C, AMENDMENT 1: C Integrity— ISO/IEC 10646-1:1993 Information technology – Universal Multiple-Octet Coded Character Set(UCS) – Part 1: Architecture and Basic Multilingual Plane2The library described in clause 7 of ISO/IEC 9899:1990 and clause 7 of ISO/IEC 9899/Amd.1:1995 is hereinafter called the Standard C Library.1)1.3 Definitions[intro.defs]1For the purposes of this International Standard, the definitions given in ISO/IEC 2382 and the followingdefinitions apply.

17.1 defines additional terms that are used only in clauses 17 through 27.2Terms that are used only in a small portion of this International Standard are defined where they are usedand italicized where they are defined.1.3.1 argument[defns.argument]an expression in the comma-separated list bounded by the parentheses in a function call expression, asequence of preprocessing tokens in the comma-separated list bounded by the parentheses in a function-likemacro invocation, the operand of throw, or an expression, type-id or template-name in the commaseparated list bounded by the angle brackets in a template instantiation.

Also known as an actual argumentor actual parameter.__________________1) With the qualifications noted in clauses 17 through 27, and in C.2, the Standard C library is a subset of the Standard C++ library.1ISO/IEC 14882:1998(E)1.3.2 diagnostic message© ISO/IEC1 General1.3.2 diagnostic message[defns.diagnostic]a message belonging to an implementation-defined subset of the implementation’s output messages.1.3.3 dynamic type[defns.dynamic.type]the type of the most derived object (1.8) to which the lvalue denoted by an lvalue expression refers.

[Example: if a pointer (8.3.1) p whose static type is “pointer to class B” is pointing to an object of class D, derivedfrom B (clause 10), the dynamic type of the expression *p is “D.” References (8.3.2) are treated similarly. ]The dynamic type of an rvalue expression is its static type.1.3.4 ill-formed programinput to a C++ implementation that is not a well-formed program (1.3.14).[defns.ill.formed]1.3.5 implementation-defined behavior[defns.impl.defined]behavior, for a well-formed program construct and correct data, that depends on the implementation andthat each implementation shall document.1.3.6 implementation limitsrestrictions imposed upon programs by the implementation.[defns.impl.limits]1.3.7 locale-specific behavior[defns.locale.specific]behavior that depends on local conventions of nationality, culture, and language that each implementationshall document.1.3.8 multibyte character[defns.multibyte]a sequence of one or more bytes representing a member of the extended character set of either the source orthe execution environment.

The extended character set is a superset of the basic character set (2.2).1.3.9 parameter[defns.parameter]an object or reference declared as part of a function declaration or definition, or in the catch clause of anexception handler, that acquires a value on entry to the function or handler; an identifier from the commaseparated list bounded by the parentheses immediately following the macro name in a function-like macrodefinition; or a template-parameter.

Parameters are also known as formal arguments or formal parameters.1.3.10 signature[defns.signature]the information about a function that participates in overload resolution (13.3): the types of its parametersand, if the function is a class member, the cv- qualifiers (if any) on the function itself and the class in which2)the member function is declared.

The signature of a template function specialization includes the types ofits template arguments (14.5.5.1).1.3.11 static type[defns.static.type]the type of an expression (3.9), which type results from analysis of the program without considering execution semantics. The static type of an expression depends only on the form of the program in which theexpression appears, and does not change while the program is executing.1.3.12 undefined behavior[defns.undefined]behavior, such as might arise upon use of an erroneous program construct or erroneous data, for which thisInternational Standard imposes no requirements.

Undefined behavior may also be expected when thisInternational Standard omits the description of any explicit definition of behavior. [Note: permissible undefined behavior ranges from ignoring the situation completely with unpredictable results, to behaving duringtranslation or program execution in a documented manner characteristic of the environment (with or without the issuance of a diagnostic message), to terminating a translation or execution (with the issuance of adiagnostic message).

Many erroneous program constructs do not engender undefined behavior; they are__________________2) Function signatures do not include return type, because that does not participate in overload resolution.2© ISO/IECISO/IEC 14882:1998(E)1 General1.3.12 undefined behaviorrequired to be diagnosed. ]1.3.13 unspecified behavior[defns.unspecified]behavior, for a well-formed program construct and correct data, that depends on the implementation. Theimplementation is not required to document which behavior occurs. [Note: usually, the range of possiblebehaviors is delineated by this International Standard. ]1.3.14 well-formed program[defns.well.formed]a C++ program constructed according to the syntax rules, diagnosable semantic rules, and the One Definition Rule (3.2).1.4 Implementation compliance[intro.compliance]1The set of diagnosable rules consists of all syntactic and semantic rules in this International Standardexcept for those rules containing an explicit notation that “no diagnostic is required” or which are describedas resulting in “undefined behavior.”2Although this International Standard states only requirements on C++ implementations, those requirementsare often easier to understand if they are phrased as requirements on programs, parts of programs, or execution of programs.

Such requirements have the following meaning:— If a program contains no violations of the rules in this International Standard, a conforming implementation shall, within its resource limits, accept and correctly execute3) that program.— If a program contains a violation of any diagnosable rule, a conforming implementation shall issue atleast one diagnostic message, except that— If a program contains a violation of a rule for which no diagnostic is required, this International Standard places no requirement on implementations with respect to that program.3For classes and class templates, the library clauses specify partial definitions. Private members (clause 11)are not specified, but each implementation shall supply them to complete the definitions according to thedescription in the library clauses.4For functions, function templates, objects, and values, the library clauses specify declarations.

Implementations shall supply definitions consistent with the descriptions in the library clauses.5The names defined in the library have namespace scope (7.3). A C++ translation unit (2.1) obtains accessto these names by including the appropriate standard library header (16.2).6The templates, classes, functions, and objects in the library have external linkage (3.5).

The implementation provides definitions for standard library entities, as necessary, while combining translation units toform a complete C++ program (2.1).7Two kinds of implementations are defined: hosted and freestanding. For a hosted implementation, thisInternational Standard defines the set of available libraries. A freestanding implementation is one in whichexecution may take place without the benefit of an operating system, and has an implementation-defined setof libraries that includes certain language-support libraries (17.4.1.3).8A conforming implementation may have extensions (including additional library functions), provided theydo not alter the behavior of any well-formed program.