cpp/string/basic string view - Revision history

Space Mission: /* Example */ upd.

2025-03-27T23:06:42Z

Example: upd.

← Older revision		Revision as of 23:06, 27 March 2025
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	int main()		int main()
	{		{
	~~constexpr std::string_view unicode[]{~~"~~▀▄─~~", "~~▄▀─~~", "~~▀─▄~~"~~, "▄─▀"};~~		#define A "▀"
			#define B "▄"
			#define C "─"

	for (int y{}, p{}; y != 6; ++y, p = ((p + 1) % 4))		constexpr std::string_view blocks[]{A B C, B A C, A C B, B C A};

			for (int y{}, p{}; y != 8; ++y, p = ((p + 1) % 4))
	{		{
	for (~~int~~ x{}; x != 16; ++x)		for (char x{}; x != 29; ++x)
	std::cout << ~~unicode~~[p];		std::cout << blocks[p];
	std::cout << '\n';		std::cout << '\n';
	}		}
	}		}
	\|output=		\|output=
	~~▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─~~		▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─
	~~▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─~~		▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─
	~~▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄~~		▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄
	~~▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀~~		▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀
	~~▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─~~		▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─
	~~▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─~~		▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─
			▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄
			▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀
	}}		}}

Xmcgcg: Added the exposition-only data members.

2025-03-27T09:27:08Z

Added the exposition-only data members.

← Older revision		Revision as of 09:27, 27 March 2025
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	Every specialization of {{tt\|std::basic_string_view}} is a {{named req\|TriviallyCopyable}} type.		Every specialization of {{tt\|std::basic_string_view}} is a {{named req\|TriviallyCopyable}} type.
	}}		}}

	~~A typical implementation holds only two members: a pointer to constant {{tt\|CharT}} and a size.~~

	Several typedefs for common character types are provided:		Several typedefs for common character types are provided:
Line 35:		Line 33:
	{{par end}}		{{par end}}

	===~~Member~~ types===		===Nested types===
	{{dsc begin}}		{{dsc begin}}
	{{dsc hitem\|~~Nested type~~\|Definition}}		{{dsc hitem\|Type\|Definition}}
	{{dsc\|{{tt\|traits_type}}\|{{tt\|Traits}}}}		{{dsc\|{{tt\|traits_type}}\|{{tt\|Traits}}}}
	{{dsc\|{{tt\|value_type}}\|{{tt\|CharT}}}}		{{dsc\|{{tt\|value_type}}\|{{tt\|CharT}}}}
Line 60:		Line 58:

	All requirements on the iterator types of a {{named req\|Container}} applies to the {{tt\|iterator}} and {{tt\|const_iterator}} types of {{tt\|basic_string_view}} as well.		All requirements on the iterator types of a {{named req\|Container}} applies to the {{tt\|iterator}} and {{tt\|const_iterator}} types of {{tt\|basic_string_view}} as well.

			===Data members===
			{{dsc begin}}
			{{dsc hitem\|Member\|Description}}
			{{dsc expos mem obj\|spec={{tt\|const_pointer}}\|data_\|id=data\|a pointer to the underlying sequence}}
			{{dsc expos mem obj\|spec={{tt\|size_type}}\|size_\|id=size\|the number of characters}}
			{{dsc end}}

	===Member functions===		===Member functions===

Cooky: ~

2024-07-12T12:31:02Z

← Older revision		Revision as of 12:31, 12 July 2024
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	{{par end}}		{{par end}}

	===~~Nested~~ types===		===Member types===
	{{dsc begin}}		{{dsc begin}}
	{{dsc hitem\|Nested type\|Definition}}		{{dsc hitem\|Nested type\|Definition}}

Space Mission: /* See also */ +operator+

2024-07-10T12:59:07Z

Space Mission: fmt

2024-02-04T05:26:20Z

fmt

← Older revision		Revision as of 05:26, 4 February 2024
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	The class template {{tt\|basic_string_view}} describes an object that can refer to a constant contiguous sequence of {{tt\|CharT}} with the first element of the sequence at position zero.		The class template {{tt\|basic_string_view}} describes an object that can refer to a constant contiguous sequence of {{tt\|CharT}} with the first element of the sequence at position zero.

	For a {{tt\|basic_string_view}} {{c\|str}}, pointers, iterators, and references to elements of {{c\|str}} are ~~invlidated~~ when an operation invalidates a pointer in the range {{range\|str.data()\|str.data() + str.size()}}.		For a {{tt\|basic_string_view}} {{c\|str}}, pointers, iterators, and references to elements of {{c\|str}} are invalidated when an operation invalidates a pointer in the range {{range\|str.data()\|str.data() + str.size()}}.

	{{rrev\|since=c++23\|		{{rrev\|since=c++23\|
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	===Example===		===Example===
	{{example\|code=		{{example
			\|code=
	#include <iostream>		#include <iostream>
	#include <string_view>		#include <string_view>
Line 173:		Line 174:
	int main()		int main()
	{		{
	constexpr std::string_view unicode[] { "▀▄─", "▄▀─", "▀─▄", "▄─▀" };		constexpr std::string_view unicode[]{"▀▄─", "▄▀─", "▀─▄", "▄─▀"};

	for (int y{}, p{}; y != 6; ++y, p = ((p + 1) % 4))		for (int y{}, p{}; y != 6; ++y, p = ((p + 1) % 4))

Xmcgcg: Added LWG issue #3203 DR (part 1/2).

2024-02-04T02:19:25Z

Added LWG issue #3203 DR (part 1/2).

← Older revision		Revision as of 02:19, 4 February 2024
Line 9:		Line 9:

	The class template {{tt\|basic_string_view}} describes an object that can refer to a constant contiguous sequence of {{tt\|CharT}} with the first element of the sequence at position zero.		The class template {{tt\|basic_string_view}} describes an object that can refer to a constant contiguous sequence of {{tt\|CharT}} with the first element of the sequence at position zero.

			For a {{tt\|basic_string_view}} {{c\|str}}, pointers, iterators, and references to elements of {{c\|str}} are invlidated when an operation invalidates a pointer in the range {{range\|str.data()\|str.data() + str.size()}}.

	{{rrev\|since=c++23\|		{{rrev\|since=c++23\|
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	{{par end}}		{{par end}}

	===~~Member~~ types===		===Nested types===
	{{dsc begin}}		{{dsc begin}}
	{{dsc hitem\|~~Member~~ type\|Definition}}		{{dsc hitem\|Nested type\|Definition}}
	{{dsc\|{{tt\|traits_type}}\|{{tt\|Traits}}}}		{{dsc\|{{tt\|traits_type}}\|{{tt\|Traits}}}}
	{{dsc\|{{tt\|value_type}}\|{{tt\|CharT}}}}		{{dsc\|{{tt\|value_type}}\|{{tt\|CharT}}}}
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	===Non-member functions===		===Non-member functions===
	{{dsc begin}}		{{dsc begin}}
	{{dsc inc\|cpp/string/basic_string_view/dsc ~~operator_cmp~~}}		{{dsc inc\|cpp/string/basic_string_view/dsc operator cmp}}
	{{dsc h2\|Input/output}}		{{dsc h2\|Input/output}}
	{{dsc inc\|cpp/string/basic_string_view/dsc ~~operator_ltlt~~}}		{{dsc inc\|cpp/string/basic_string_view/dsc operator ltlt}}
	{{dsc end}}		{{dsc end}}

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	▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─		▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─▄▀─
	}}		}}

			===Defect reports===
			{{dr list begin}}
			{{dr list item\|wg=lwg\|dr=3203\|std=C++17\|before=only pointers, iterators, and references<br>returned from the member functions of<br>{{tt\|basic_string_view}} might be invalidated\|after=all pointers, iterators, and references<br>to elements of {{tt\|basic_string_view}}<br>may be invalidated}}
			{{dr list end}}

	===See also===		===See also===

Space Mission: reformat "Deduction guides" by analogy with container's main pages, e.g. map

2023-12-21T04:39:50Z

reformat "Deduction guides" by analogy with container's main pages, e.g. map

← Older revision		Revision as of 04:39, 21 December 2023
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	This specialization of {{lc\|ranges::enable_view}} makes {{tt\|basic_string_view}} satisfy {{lconcept\|view}}.		This specialization of {{lc\|ranges::enable_view}} makes {{tt\|basic_string_view}} satisfy {{lconcept\|view}}.

	==={{rl\|deduction guides\|Deduction guides~~}}{{mark since c++20~~}}===		{{rrev\|since=c++20\|
			==={{rl\|deduction guides\|Deduction guides}}===
			}}

	===Notes===		===Notes===

Andreas Krug: fmt

2023-07-07T16:50:36Z

fmt

← Older revision		Revision as of 16:50, 7 July 2023
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	{{par begin}}		{{par begin}}
	{{par\|CharT\|character type}}		{{par\|CharT\|character type}}
	{{par\|Traits\|{{named req\|CharTraits}} class specifying the operations on the character type. Like for {{lc\|std::basic_string}}, {{tt\|Traits::char_type}} must name the same type as {{tt\|CharT}} or the program is ill-formed. }}		{{par\|Traits\|{{named req\|CharTraits}} class specifying the operations on the character type. Like for {{lc\|std::basic_string}}, {{tt\|Traits::char_type}} must name the same type as {{tt\|CharT}} or the program is ill-formed.}}
	{{par end}}		{{par end}}

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	===Literals===		===Literals===
	{{dsc begin}}		{{dsc begin}}
	{{dsc namespace\|[[cpp/header/string_view#Synopsis\|std::literals::string_view_literals]]\|inline=true }}		{{dsc namespace\|[[cpp/header/string_view#Synopsis\|std::literals::string_view_literals]]\|inline=true}}
	{{dsc inc\|cpp/string/basic_string_view/dsc operator""sv}}		{{dsc inc\|cpp/string/basic_string_view/dsc operator""sv}}
	{{dsc end}}		{{dsc end}}
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	{{source\|1=		{{source\|1=
	std::string_view good{"a string literal"};		std::string_view good{"a string literal"};
	// "Good" case: `good` points to a static array. ~~String~~		// "Good" case: `good` points to a static array.
	// literals reside in persistent data storage.		// String literals reside in persistent data storage.

	std::string_view bad{"a temporary string"s};		std::string_view bad{"a temporary string"s};
	// "Bad" case: `bad` holds a dangling pointer since the std::string temporary,		// "Bad" case: `bad` holds a dangling pointer since the std::string temporary,
	// created by std::operator""s, will be destroyed at the end of the statement.		// created by std::operator""s, will be destroyed at the end of the statement.
	}}		}}

31.201.234.47: output is deterministic

2023-07-07T11:44:57Z

output is deterministic

← Older revision		Revision as of 11:44, 7 July 2023
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	}		}
	}		}
	~~\|p=true~~
	\|output=		\|output=
	▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─		▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─▀▄─

Xmcgcg: Minor fix.

2023-04-07T06:51:39Z

Minor fix.

← Older revision		Revision as of 06:51, 7 April 2023
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	{{par begin}}		{{par begin}}
	{{par\|CharT\|character type}}		{{par\|CharT\|character type}}
	{{par\|Traits\|{{named req\|CharTraits}} class specifying the operations on the character type. Like for {{tt\|basic_string}}, {{c\|Traits::char_type}} must name the same type as {{c\|CharT}} or the program is ill-formed. }}		{{par\|Traits\|{{named req\|CharTraits}} class specifying the operations on the character type. Like for {{lc\|std::basic_string}}, {{tt\|Traits::char_type}} must name the same type as {{tt\|CharT}} or the program is ill-formed. }}
	{{par end}}		{{par end}}

← Older revision		Revision as of 12:59, 10 July 2024
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	{{dsc begin}}		{{dsc begin}}
	{{dsc inc\|cpp/string/dsc basic_string}}		{{dsc inc\|cpp/string/dsc basic_string}}
			{{dsc inc\|cpp/string/basic_string/dsc operator+}}
	{{dsc inc\|cpp/container/dsc span}}		{{dsc inc\|cpp/container/dsc span}}
	{{dsc inc\|cpp/utility/dsc initializer_list}}		{{dsc inc\|cpp/utility/dsc initializer_list}}