std::filesystem::path::concat, std::filesystem::path::operator+=

path& operator+=( const path& p );

path& operator+=( const string_type& str );
path& operator+=( std::basic_string_view<value_type> str );

path& operator+=( const value_type* ptr );

path& operator+=( value_type x );

template< class CharT >
path& operator+=( CharT x );

template< class Source >
path& operator+=( const Source& source );

template< class Source >
path& concat( const Source& source );

template< class InputIt >
path& concat( InputIt first, InputIt last );

Concatenates the current path and the argument

(6) and (7) participate in overload resolution only if Source and path are not the same type, and either:

• Source is a specialization of std::basic_string or std::basic_string_view, or
• std::iterator_traits<std::decay_t<Source>>::value_type is valid and denotes a possibly const-qualified encoding character type (char, char8_t, (since C++20)char16_t, char32_t, or wchar_t).

Parameters

Return value

*this

Exceptions

May throw std::bad_alloc if memory allocation fails.

Notes

Unlike with append() or operator/=, additional directory separators are never introduced.

Example

#include <filesystem>
#include <iostream>
#include <string>
 
int main()
{
    std::filesystem::path p1; // an empty path
    p1 += "var"; // does not insert a separator
    std::cout << R"("" + "var" --> )" << p1 << '\n';
    p1 += "lib"; // does not insert a separator
    std::cout << R"("var" + "lib" --> )" << p1 << '\n';
    auto str = std::string{"1234567"};
    p1.concat(std::begin(str) + 3, std::end(str) - 1);
    std::cout << "p1.concat --> " << p1 << '\n';
}

"" + "var" --> "var"
"var" + "lib" --> "varlib"
p1.concat --> "varlib456"

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also