C++ Standard Library headers

 

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

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Standard Library headers

Language Support
<cstddef> <cstdlib> <version> <limits> <climits>	<cfloat> <cstdint> <new> <typeinfo>	<source_location> <exception> <initializer_list> <compare>	<coroutine> <csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator>	<bitset> <tuple> <optional> <any>	<variant> <type_traits> <ratio> <chrono>	<typeindex> <functional> <ctime>
Strings
<string> <string_view> <cstring>	<charconv> <format>	<cctype> <cwctype>	<cwchar> <cuchar>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Ranges
<ranges>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<bit> <numbers>	<cfenv> <cmath>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
Regular expressions
<regex>
Filesystem support
<filesystem>
Thread support
<thread> <atomic> <mutex>	<shared_mutex> <condition_variable> <future>	<stop_token> <semaphore>	<latch> <barrier>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

 

The interface of C++ standard library is defined by the following collection of headers.

Concepts library
<concepts> (C++20)	Fundamental library concepts
Coroutines library
<coroutine> (C++20)	Coroutine support library
Utilities library
<cstdlib>	General purpose utilities: program control, dynamic memory allocation, random numbers, sort and search
<csignal>	Functions and macro constants for signal management
<csetjmp>	Macro (and function) that saves (and jumps) to an execution context
<cstdarg>	Handling of variable length argument lists
<typeinfo>	Runtime type information utilities
<typeindex> (C++11)	std::type_index
<type_traits> (C++11)	Compile-time type information
<bitset>	std::bitset class template
<functional>	Function objects, Function invocations, Bind operations and Reference wrappers
<utility>	Various utility components
<ctime>	C-style time/date utilites
<chrono> (C++11)	C++ time utilites
<cstddef>	Standard macros and typedefs
<initializer_list> (C++11)	std::initializer_list class template
<tuple> (C++11)	std::tuple class template
<any> (C++17)	std::any class
<optional> (C++17)	std::optional class template
<variant> (C++17)	std::variant class template
<compare> (C++20)	Three-way comparison operator support
<version> (C++20)	Supplies implementation-dependent library information
<source_location> (C++20)	Supplies means to obtain source code location
Dynamic memory management
<new>	Low-level memory management utilities
<memory>	High-level memory management utilities
<scoped_allocator> (C++11)	Nested allocator class
<memory_resource> (C++17)	Polymorphic allocators and memory resources
Numeric limits
<climits>	Limits of integral types
<cfloat>	Limits of floating-point types
<cstdint> (C++11)	Fixed-width integer types and limits of other types
<cinttypes> (C++11)	Formatting macros, intmax_t and uintmax_t math and conversions
<limits>	Uniform way to query properties of arithmetic types
Error handling
<exception>	Exception handling utilities
<stdexcept>	Standard exception objects
<cassert>	Conditionally compiled macro that compares its argument to zero
<system_error> (C++11)	Defines std::error_code, a platform-dependent error code
<cerrno>	Macro containing the last error number
Strings library
<cctype>	Functions to determine the category of narrow characters
<cwctype>	Functions to determine the catagory of wide characters
<cstring>	Various narrow character string handling functions
<cwchar>	Various wide and multibyte string handling functions
<cuchar> (C++11)	C-style Unicode character conversion functions
<string>	std::basic_string class template
<string_view> (C++17)	std::basic_string_view class template
<charconv> (C++17)	std::to_chars and std::from_chars
<format> (C++20)	Formatting library including std::format
Containers library
<array> (C++11)	std::array container
<vector>	std::vector container
<deque>	std::deque container
<list>	std::list container
<forward_list> (C++11)	std::forward_list container
<set>	std::set and std::multiset associative containers
<map>	std::map and std::multimap associative containers
<unordered_set> (C++11)	std::unordered_set and std::unordered_multiset unordered associative containers
<unordered_map> (C++11)	std::unordered_map and std::unordered_multimap unordered associative containers
<stack>	std::stack container adaptor
<queue>	std::queue and std::priority_queue container adaptors
<span> (C++20)	std::span view
Iterators library
<iterator>	Range iterators
Ranges library
<ranges> (C++20)	Range access, primitives, requirements, utilities and adaptors
Algorithms library
<algorithm>	Algorithms that operate on ranges
<execution> (C++17)	Predefined execution policies for parallel versions of the algorithms
Numerics library
<cmath>	Common mathematics functions
<complex>	Complex number type
<valarray>	Class for representing and manipulating arrays of values
<random> (C++11)	Random number generators and distributions
<numeric>	Numeric operations on values in ranges
<ratio> (C++11)	Compile-time rational arithmetic
<cfenv> (C++11)	Floating-point environment access functions
<bit> (C++20)	Bit manipulation functions
<numbers> (C++20)	Math constants
Localization library
<locale>	Localization utilities
<clocale>	C localization utilities
<codecvt> (C++11)(deprecated in C++17)	Unicode conversion facilities
Input/output library
<iosfwd>	Forward declarations of all classes in the input/output library
<ios>	std::ios_base class, std::basic_ios class template and several typedefs
<istream>	std::basic_istream class template and several typedefs
<ostream>	std::basic_ostream, std::basic_iostream class templates and several typedefs
<iostream>	Several standard stream objects
<fstream>	std::basic_fstream, std::basic_ifstream, std::basic_ofstream class templates and several typedefs
<sstream>	std::basic_stringstream, std::basic_istringstream, std::basic_ostringstream class templates and several typedefs
<syncstream> (C++20)	std::basic_osyncstream, std::basic_syncbuf, and typedefs
<strstream> (deprecated in C++98)	std::strstream, std::istrstream, std::ostrstream
<iomanip>	Helper functions to control the format of input and output
<streambuf>	std::basic_streambuf class template
<cstdio>	C-style input-output functions
Filesystem library
<filesystem> (C++17)	std::path class and supporting functions
Regular Expressions library
<regex> (C++11)	Classes, algorithms and iterators to support regular expression processing
Atomic Operations library
<atomic> (C++11)	Atomic operations library
Thread support library
<thread> (C++11)	std::thread class and supporting functions
<stop_token> (C++20)	Stop tokens for std::jthread
<mutex> (C++11)	Mutual exclusion primitives
<shared_mutex> (C++14)	Shared mutual exclusion primitives
<future> (C++11)	Primitives for asynchronous computations
<condition_variable> (C++11)	Thread waiting conditions
<semaphore> (C++20)	Semaphores
<latch> (C++20)	Latches
<barrier> (C++20)	Barriers

C compatibility headers

For some of the C standard library headers of the form xxx.h, the C++ standard library both includes an identically-named header and another header of the form cxxx (all meaningful cxxx headers are listed above).

With the exception of complex.h , each xxx.h header included in the C++ standard library places in the global namespace each name that the corresponding cxxx header would have placed in the std namespace.

These headers are allowed to also declare the same names in the std namespace, and the corresponding cxxx headers are allowed to also declare the same names in the global namespace: including <cstdlib> definitely provides std::malloc and may also provide ::malloc. Including <stdlib.h> definitely provides ::malloc and may also provide std::malloc. This applies even to functions and function overloads that are not part of C standard library.

<assert.h> (deprecated)	Behaves same as <cassert>
<ctype.h> (deprecated)	Behaves as if each name from <cctype> is placed in global namespace
<errno.h> (deprecated)	Behaves same as <cerrno>
<fenv.h> (C++11)(deprecated)	Behaves as if each name from <cfenv> is placed in global namespace
<float.h> (deprecated)	Behaves same as <cfloat>
<inttypes.h> (C++11)(deprecated)	Behaves as if each name from <cinttypes> is placed in global namespace
<limits.h> (deprecated)	Behaves same as <climits>
<locale.h> (deprecated)	Behaves as if each name from <clocale> is placed in global namespace
<math.h> (deprecated)	Behaves as if each name from <cmath> is placed in global namespace, except for names of mathematical special functions
<setjmp.h> (deprecated)	Behaves as if each name from <csetjmp> is placed in global namespace
<signal.h> (deprecated)	Behaves as if each name from <csignal> is placed in global namespace
<stdarg.h> (deprecated)	Behaves as if each name from <cstdarg> is placed in global namespace
<stddef.h> (deprecated)	Behaves as if each name from <cstddef> is placed in global namespace, except for names of std::byte and related functions
<stdint.h> (C++11)(deprecated)	Behaves as if each name from <cstdint> is placed in global namespace
<stdio.h> (deprecated)	Behaves as if each name from <cstdio> is placed in global namespace
<stdlib.h> (deprecated)	Behaves as if each name from <cstdlib> is placed in global namespace
<string.h> (deprecated)	Behaves as if each name from <cstring> is placed in global namespace
<time.h> (deprecated)	Behaves as if each name from <ctime> is placed in global namespace
<uchar.h> (C++11)(deprecated)	Behaves as if each name from <cuchar> is placed in global namespace
<wchar.h> (deprecated)	Behaves as if each name from <cwchar> is placed in global namespace
<wctype.h> (deprecated)	Behaves as if each name from <cwctype> is placed in global namespace

Empty C headers

The headers <complex.h>, <ccomplex>, <tgmath.h>, and <ctgmath> do not contain any content from the C standard library and instead merely include other headers from the C++ standard library. The use of all these headers is deprecated in C++.

<ccomplex> (C++11)(deprecated in C++17)(removed in C++20)	Simply includes the header <complex>
<complex.h> (C++11)(deprecated)	Simply includes the header <complex>
<ctgmath> (C++11)(deprecated in C++17)(removed in C++20)	Simply includes the headers <complex> and <cmath>: the overloads equivalent to the contents of the C header tgmath.h are already provided by those headers
<tgmath.h> (C++11)(deprecated)	Simply includes the headers <complex> and <cmath>

Meaningless C headers

The headers <ciso646>, <cstdalign>, and <cstdbool> are meaningless in C++ because the macros they provide in C are language keywords in C++.

<ciso646> (removed in C++20)	Empty header. The macros that appear in iso646.h in C are keywords in C++
<iso646.h> (deprecated)	Has no effect
<cstdalign> (C++11)(deprecated in C++17)(removed in C++20)	Defines one compatibility macro constant
<stdalign.h> (C++11)(deprecated)	Defines one compatibility macro constant
<cstdbool> (C++11)(deprecated in C++17)(removed in C++20)	Defines one compatibility macro constant
<stdbool.h> (C++11)(deprecated)	Defines one compatibility macro constant

Unsupported C headers

The C headers <stdatomic.h>, <stdnoreturn.h>, and <threads.h> are not included in C++ and have no cxxx equivalents.

Experimental libraries

C++ TR's/TS's also define several collections of headers.