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

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Concepts (concepts TS)

Extensions for concurrency (concurrency TS)

 

Filesystem library

Classes
filesystem::path filesystem::filesystem_error filesystem::directory_entry filesystem::directory_iterator filesystem::recursive_directory_iterator filesystem::file_status	filesystem::space_info filesystem::file_type filesystem::perms filesystem::copy_options filesystem::directory_options filesystem::file_time_type
Functions
filesystem::absolute filesystem::system_complete filesystem::canonical filesystem::copy filesystem::copy_file filesystem::copy_symlink filesystem::create_directory filesystem::create_directories filesystem::create_hard_link filesystem::create_symlink filesystem::create_directory_symlink filesystem::current_path filesystem::exists filesystem::equivalent	filesystem::file_size filesystem::hard_link_count filesystem::last_write_time filesystem::permissions filesystem::read_symlink filesystem::remove filesystem::remove_all filesystem::rename filesystem::resize_file filesystem::space filesystem::status filesystem::symlink_status filesystem::temp_directory_path
File types
filesystem::is_block_file filesystem::is_character_file filesystem::is_directory filesystem::is_empty filesystem::status_known	filesystem::is_fifo filesystem::is_other filesystem::is_regular_file filesystem::is_socket filesystem::is_symlink

 

path

Member functions
path::path path::~path path::operator= path::assign path::appendoperator /= path::concatoperator += path::clear path::make_preferred path::remove_filename path::replace_filename path::replace_extension path::swap path::compare	path::c_strpath::nativeoperator string_type path::stringpath::u8stringpath::u16stringpath::u32stringpath::wstring path::generic_stringpath::generic_u8stringpath::generic_u16stringpath::generic_u32stringpath::generic_wstring path::beginpath::end
Path decomposition
path::root_name path::root_directory path::root_path path::relative_path path::parent_path path::filename path::stem path::extension path::empty	path::has_root_pathpath::has_root_namepath::has_root_directorypath::has_relative_pathpath::has_parent_pathpath::has_filenamepath::has_stempath::has_extension path::is_absolutepath::is_relative
Non-member functions
swap(path)
operator==operator!=operator<operator<=operator>operator>=
operator/
operator<<operator>>
u8path

 

path& operator+=( const path& p );	(1)	(filesystem TS)
path& operator+=( const string_type& str );	(2)	(filesystem TS)
path& operator+=( const value_type* ptr );	(3)	(filesystem TS)
path& operator+=( value_type x );	(4)	(filesystem TS)
template< class Source > path& operator+=( const Source& source );	(5)	(filesystem TS)
template< class CharT > path& operator+=( CharT x );	(6)	(filesystem TS)
template< class Source > path& concat( const Source& source );	(7)	(filesystem TS)
template< class InputIt > path& concat( InputIterator first, InputIterator last );	(8)	(filesystem TS)

Concatenates the current path and the argument

1) Concatenates *this and p in such a way that native() of the result is exactly original native() concatenated with p.native()

2) Same as (1), except the resulting native() is a concatenation of the original {native() and the string str

3) Same as (1), except the resulting native() is a concatenation of the original native() and the null-terminated string whose first character is pointed to by ptr

4) Same as (1), except the resulting native() is a concatenation of the original native() and the single character x

5) Same as (1), except the resulting native() is a concatenation of the original native() and the sequence (which may be in portable or native format) represented by source, which may be std::basic_string, null-terminated multicharacter string, or an input iterator pointing to a null-terminated multicharacter sequence.

6) Same as (4), except that character conversion may be performed

7) Same as (5)

8) Same as (5), except that the sequence is represented by any iterator pair that designates a multicharacter string.

Parameters

p	-	path to append
str	-	string to append
ptr	-	pointer to the beginning of a null-terminated string to append
x	-	single character to append
source	-	std::basic_string, null-terminated multicharacter string, or an input iterator pointing to a null-terminated multicharacter sequence, which represents a path name (either in portable or in native format)
first, last	-	pair of InputIterators that specify a multicharacter sequence that represents a path name
Type requirements
- InputIt must meet the requirements of InputIterator.
- The value type of InputIt must be one of the encoded character types (char, wchar_t, char16_t and char32_t)
- CharT must be one of the encoded character types (char, wchar_t, char16_t and char32_t)

Return value

*this

Exceptions

May throw filesystem_error on underlying OS API errors or std::bad_alloc if memory allocation fails.

Notes

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

Example

Run this code

#include <iostream>
#include <experimental/filesystem>
namespace fs = std::experimental::filesystem;
int main() {
    fs::path p1; // empty path
    p1 += "var"; // does not insert a separator
    std::cout << "\"\" + \"var\" == " << p1 << '\n';
    p1 += "lib"; // does not insert a separator
    std::cout << "\"\" + \"var\" + \"lib\" == " << p1 << '\n';
}

Output:

"" + "var" == "var"
"" + "var" + "lib" == "varlib"

See also

appendoperator/=	appends elements to the path (public member function)
operator/	concatenates two paths with a directory separator (function)