174 lines
11 KiB
Markdown
174 lines
11 KiB
Markdown
[lex.icon]
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# 5 Lexical conventions [[lex]](./#lex)
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## 5.13 Literals [[lex.literal]](lex.literal#lex.icon)
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### 5.13.2 Integer literals [lex.icon]
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[integer-literal:](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")
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[*binary-literal*](#nt:binary-literal "5.13.2 Integer literals [lex.icon]") [*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*octal-literal*](#nt:octal-literal "5.13.2 Integer literals [lex.icon]") [*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*decimal-literal*](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]") [*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*hexadecimal-literal*](#nt:hexadecimal-literal "5.13.2 Integer literals [lex.icon]") [*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")opt
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[binary-literal:](#nt:binary-literal "5.13.2 Integer literals [lex.icon]")
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0b [*binary-digit*](#nt:binary-digit "5.13.2 Integer literals [lex.icon]")
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0B [*binary-digit*](#nt:binary-digit "5.13.2 Integer literals [lex.icon]")
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[*binary-literal*](#nt:binary-literal "5.13.2 Integer literals [lex.icon]") 'opt [*binary-digit*](#nt:binary-digit "5.13.2 Integer literals [lex.icon]")
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[octal-literal:](#nt:octal-literal "5.13.2 Integer literals [lex.icon]")
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0
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[*octal-literal*](#nt:octal-literal "5.13.2 Integer literals [lex.icon]") 'opt [*octal-digit*](#nt:octal-digit "5.13.2 Integer literals [lex.icon]")
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[decimal-literal:](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]")
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[*nonzero-digit*](#nt:nonzero-digit "5.13.2 Integer literals [lex.icon]")
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[*decimal-literal*](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]") 'opt [*digit*](lex.name#nt:digit "5.11 Identifiers [lex.name]")
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[hexadecimal-literal:](#nt:hexadecimal-literal "5.13.2 Integer literals [lex.icon]")
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[*hexadecimal-prefix*](#nt:hexadecimal-prefix "5.13.2 Integer literals [lex.icon]") [*hexadecimal-digit-sequence*](#nt:hexadecimal-digit-sequence "5.13.2 Integer literals [lex.icon]")
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[binary-digit:](#nt:binary-digit "5.13.2 Integer literals [lex.icon]") one of
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0 1
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[octal-digit:](#nt:octal-digit "5.13.2 Integer literals [lex.icon]") one of
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0 1 2 3 4 5 6 7
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[nonzero-digit:](#nt:nonzero-digit "5.13.2 Integer literals [lex.icon]") one of
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1 2 3 4 5 6 7 8 9
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[hexadecimal-prefix:](#nt:hexadecimal-prefix "5.13.2 Integer literals [lex.icon]") one of
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0x 0X
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[hexadecimal-digit-sequence:](#nt:hexadecimal-digit-sequence "5.13.2 Integer literals [lex.icon]")
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[*hexadecimal-digit*](#nt:hexadecimal-digit "5.13.2 Integer literals [lex.icon]")
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[*hexadecimal-digit-sequence*](#nt:hexadecimal-digit-sequence "5.13.2 Integer literals [lex.icon]") 'opt [*hexadecimal-digit*](#nt:hexadecimal-digit "5.13.2 Integer literals [lex.icon]")
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[hexadecimal-digit:](#nt:hexadecimal-digit "5.13.2 Integer literals [lex.icon]") one of
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0 1 2 3 4 5 6 7 8 9
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a b c d e f
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A B C D E F
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[integer-suffix:](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")
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[*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]") [*long-suffix*](#nt:long-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]") [*long-long-suffix*](#nt:long-long-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]") [*size-suffix*](#nt:size-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*long-suffix*](#nt:long-suffix "5.13.2 Integer literals [lex.icon]") [*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*long-long-suffix*](#nt:long-long-suffix "5.13.2 Integer literals [lex.icon]") [*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]")opt
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[*size-suffix*](#nt:size-suffix "5.13.2 Integer literals [lex.icon]") [*unsigned-suffix*](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]")opt
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[unsigned-suffix:](#nt:unsigned-suffix "5.13.2 Integer literals [lex.icon]") one of
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u U
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[long-suffix:](#nt:long-suffix "5.13.2 Integer literals [lex.icon]") one of
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l L
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[long-long-suffix:](#nt:long-long-suffix "5.13.2 Integer literals [lex.icon]") one of
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ll LL
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[size-suffix:](#nt:size-suffix "5.13.2 Integer literals [lex.icon]") one of
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z Z
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L1268)
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In an [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]"),
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the sequence of[*binary-digit*](#nt:binary-digit "5.13.2 Integer literals [lex.icon]")*s*,[*octal-digit*](#nt:octal-digit "5.13.2 Integer literals [lex.icon]")*s*,[*digit*](lex.name#nt:digit "5.11 Identifiers [lex.name]")*s*, or[*hexadecimal-digit*](#nt:hexadecimal-digit "5.13.2 Integer literals [lex.icon]")*s* is interpreted as a base N integer as shown in Table [7](#tab:lex.icon.base "Table 7: Base of integer-literals");
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the lexically first digit of the sequence of digits is the most significant[.](#1.sentence-1)
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[*Note [1](#note-1)*:
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The prefix and any optional separating single quotes are ignored
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when determining the value[.](#1.sentence-2)
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â *end note*]
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Table [7](#tab:lex.icon.base) — Base of [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")*s* [[tab:lex.icon.base]](./tab:lex.icon.base)
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| [ð](#tab:lex.icon.base-row-1)<br>**Kind of [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")** | **base N** |
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| --- | --- |
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| [ð](#tab:lex.icon.base-row-2)<br>[*binary-literal*](#nt:binary-literal "5.13.2 Integer literals [lex.icon]") | 2 |
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| [ð](#tab:lex.icon.base-row-3)<br>[*octal-literal*](#nt:octal-literal "5.13.2 Integer literals [lex.icon]") | 8 |
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| [ð](#tab:lex.icon.base-row-4)<br>[*decimal-literal*](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]") | 10 |
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| [ð](#tab:lex.icon.base-row-5)<br>[*hexadecimal-literal*](#nt:hexadecimal-literal "5.13.2 Integer literals [lex.icon]") | 16 |
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L1297)
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The [*hexadecimal-digit*](#nt:hexadecimal-digit "5.13.2 Integer literals [lex.icon]")*s*a through f and A through F have decimal values ten through fifteen[.](#2.sentence-1)
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[*Example [1](#example-1)*:
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The number twelve can be written 12, 014,0XC, or 0b1100[.](#2.sentence-2)
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The [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")*s* 1048576,1'048'576, 0X100000, 0x10'0000, and0'004'000'000 all have the same value[.](#2.sentence-3)
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â *end example*]
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L1308)
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The type of an [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") is
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the first type in the list in Table [8](#tab:lex.icon.type "Table 8: Types of integer-literals") corresponding to its optional [*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]") in which its value can be represented[.](#3.sentence-1)
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Table [8](#tab:lex.icon.type) — Types of [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")*s* [[tab:lex.icon.type]](./tab:lex.icon.type)
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| [ð](#tab:lex.icon.type-row-1)<br>**[*integer-suffix*](#nt:integer-suffix "5.13.2 Integer literals [lex.icon]")** | **[*decimal-literal*](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]")** | **[*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") other than [*decimal-literal*](#nt:decimal-literal "5.13.2 Integer literals [lex.icon]")** |
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| --- | --- | --- |
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| [ð](#tab:lex.icon.type-row-2)<br>none | int | int |
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| [ð](#tab:lex.icon.type-row-3) | long int | unsigned int |
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| [ð](#tab:lex.icon.type-row-4) | long long int | long int |
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| [ð](#tab:lex.icon.type-row-5) | | unsigned long int |
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| [ð](#tab:lex.icon.type-row-6) | | long long int |
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| [ð](#tab:lex.icon.type-row-7) | | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-8)<br>u or U | unsigned int | unsigned int |
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| [ð](#tab:lex.icon.type-row-9) | unsigned long int | unsigned long int |
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| [ð](#tab:lex.icon.type-row-10) | unsigned long long int | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-11)<br>l or L | long int | long int |
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| [ð](#tab:lex.icon.type-row-12) | long long int | unsigned long int |
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| [ð](#tab:lex.icon.type-row-13) | | long long int |
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| [ð](#tab:lex.icon.type-row-14) | | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-15)<br>Both u or U | unsigned long int | unsigned long int |
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| [ð](#tab:lex.icon.type-row-16)<br>and l or L | unsigned long long int | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-17)<br>ll or LL | long long int | long long int |
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| [ð](#tab:lex.icon.type-row-18) | | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-19)<br>Both u or U | unsigned long long int | unsigned long long int |
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| [ð](#tab:lex.icon.type-row-20)<br>and ll or LL | | |
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| [ð](#tab:lex.icon.type-row-21)<br>z or Z | the signed integer type corresponding | the signed integer type |
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| [ð](#tab:lex.icon.type-row-22) | to std::size_t ([[support.types.layout]](support.types.layout "17.2.4 Sizes, alignments, and offsets")) | corresponding to std::size_t |
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| [ð](#tab:lex.icon.type-row-23) | | std::size_t |
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| [ð](#tab:lex.icon.type-row-24)<br>Both u or U | std::size_t | std::size_t |
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| [ð](#tab:lex.icon.type-row-25)<br>and z or Z | | |
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[4](#4)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L1399)
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Except for [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]")*s* containing
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a [*size-suffix*](#nt:size-suffix "5.13.2 Integer literals [lex.icon]"),
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if the value of an [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") cannot be represented by any type in its list and
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an extended integer type ([[basic.fundamental]](basic.fundamental "6.9.2 Fundamental types")) can represent its value,
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it may have that extended integer type[.](#4.sentence-1)
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If all of the types in the list for the [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") are signed,
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the extended integer type is signed[.](#4.sentence-2)
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If all of the types in the list for the [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") are unsigned,
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the extended integer type is unsigned[.](#4.sentence-3)
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If the list contains both signed and unsigned types,
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the extended integer type may be signed or unsigned[.](#4.sentence-4)
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If an [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") cannot be represented by any of the allowed types,
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the program is ill-formed[.](#4.sentence-5)
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[*Note [2](#note-2)*:
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An [*integer-literal*](#nt:integer-literal "5.13.2 Integer literals [lex.icon]") with a z or Z suffix
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is ill-formed if it cannot be represented by std::size_t[.](#4.sentence-6)
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â *end note*]
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