std::basic_string_view<CharT,Traits>::starts_with

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string_view

Member functions basic_string_view::basic_string_view basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap

Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::starts_with (C++20) basic_string_view::ends_with (C++20) basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u8string_view>hash<std::u16string_view>hash<std::u32string_view> (C++20) Deduction guides(C++20)

 

constexpr bool starts_with( basic_string_view sv ) const noexcept;	(1)	(since C++20)
constexpr bool starts_with( CharT c ) const noexcept;	(2)	(since C++20)
constexpr bool starts_with( const CharT* s ) const;	(3)	(since C++20)

Checks if the string view begins with the given prefix, where

1) the prefix is a string view. Effectively returns size() >= sv.size() && compare(0, sv.size(), sv) == 0

2) the prefix is a single character. Effectively returns !empty() && Traits::eq(front(), c)

3) the prefix is a null-terminated character string. Effectively returns starts_with(basic_string_view(s))

Parameters

sv	-	a string view which may be a result of implicit conversion from std::basic_string
c	-	a single character
s	-	a null-terminated character string

Return value

true if the string view begins with the provided prefix, false otherwise.

See also

ends_with (C++20)	checks if the string view ends with the given suffix (public member function)
starts_with (C++20)	checks if the string starts with the given prefix (public member function of std::basic_string<CharT,Traits,Allocator>)
ends_with (C++20)	checks if the string ends with the given suffix (public member function of std::basic_string<CharT,Traits,Allocator>)
compare	compares two views (public member function)