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

 

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basic_string

basic_string_view (C++17)

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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 Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Operations basic_string_view::copy basic_string_view::substr basic_string_view::subview (C++26) basic_string_view::compare basic_string_view::starts_with (C++20) basic_string_view::ends_with (C++20) basic_string_view::contains (C++23) 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

Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap 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 std::basic_string_view<CharT, Traits> subview( size_type pos = 0, size_type count = npos ) const;		(since C++26)

See More

Returns a view of the substring [pos, pos + rlen), where rlen is the smaller of count and size() - pos.

Parameters

pos	-	position of the first character
count	-	requested length

Return value

View of the substring [pos, pos + rlen).

Exceptions

std::out_of_range if pos > size().

Complexity

Constant.

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_string_subview	202506L	(C++26)	std::basic_string_view::subview, std::basic_string::subview

Example

Run this code

#include <cassert>
#include <iostream>
#include <string_view>

int main()
{
    const std::string_view s{"Life is life!"};
    assert(s.subview(5) == "is life!");
    assert(s.subview(5, 13) == "is life!");
    assert(s.subview(5, 2) == "is");

    try
    {
        // pos is out of bounds, throws
        const auto pos{s.length() + 13};
        [[maybe_unused]] auto x_x{s.subview(pos)};
    }
    catch (const std::out_of_range& ex)
    {
        std::cout << "Exception: " << ex.what() << '\n';
    }
}

Possible output:

Exception: basic_string_view::substr: __pos (which is 26) > __size (which is 13)

See also

substr	returns a substring (public member function)
subview (C++26)	returns a sub-view (public member function)