Standard library header <cstddef>

 

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)

Filesystem library (C++17)

Technical Specifications

 

Standard Library header files

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

 

This header was originally in the C standard library as <stddef.h>.

This header is part of the utility library.

Macros

NULL	implementation-defined null pointer constant (macro constant)
offsetof	byte offset from the beginning of a standard-layout type to specified member (function macro)

Types

size_t	unsigned integer type returned by the sizeof operator (typedef)
ptrdiff_t	signed integer type returned when subtracting two pointers (typedef)
nullptr_t (C++11)	the type of the null pointer literal nullptr (typedef)
max_align_t (C++11)	POD type with alignment requirement as great as any other scalar type (typedef)

Synopsis

namespace std {
    using ptrdiff_t = /*see definition*/ ;
    using size_t = /*see definition*/ ;
    using max_align_t = /*see definition*/ ;
    using nullptr_t = decltype(nullptr);
}
#define NULL /*see definition*/
#define offsetof(P, D) /*see definition*/

Notes

• NULL is also defined in the following headers:
  • <clocale>
  • <ctime>
  • <cstring>
  • <cstdio>
  • <cwchar>
• std::size_t is also defined in the following headers:
  • <ctime>
  • <cstring>
  • <cstdio>
  • <cwchar>