C++ keyword: long

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General 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)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

C++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (C++11)	while do-while
Jump statements
continue - break	goto - return
Functions
Function declaration
Lambda function expression
inline specifier
Dynamic exception specifications (until C++17*)
noexcept specifier (C++11)
Exceptions
throw-expression try block	handler
Namespaces
Namespace declaration	Namespace aliases
Types
Fundamental types Enumeration types Function types	Class/struct types Union types
Specifiers
const/volatile decltype (C++11) auto (C++11)	constexpr (C++11) consteval (C++20) constinit (C++20)
Storage duration specifiers
Initialization
Default-initialization Value-initialization Zero-initialization Copy-initialization Direct-initialization	Aggregate initialization List-initialization (C++11)   Constant initialization Reference initialization

Expressions
Value categories Order of evaluation	Operators Operator precedence
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
Utilities
Attributes (C++11)
Types
typedef declaration
Type alias declaration (C++11)
Casts
Implicit conversions static_cast const_cast	Explicit conversions dynamic_cast reinterpret_cast
Memory allocation
new expression	delete expression
Classes
Class declaration Constructors this pointer	Access specifiers friend specifier
Class-specific function properties
Virtual function override specifier (C++11)   final specifier (C++11)	explicit (C++11) static
Special member functions
Default constructor Copy constructor Move constructor (C++11)	Copy assignment Move assignment (C++11) Destructor
Templates
Class template Function template	Template specialization Parameter packs (C++11)
Miscellaneous
Inline assembly	History of C++

 

Keywords

alignas (C++11) alignof (C++11) and and_eq asm auto (*) bitand bitor bool break case catch char char8_t (C++20) char16_t (C++11) char32_t (C++11) class compl concept (C++20) const consteval (C++20)     constexpr (C++11) constinit (C++20) const_cast continue co_await (C++20) co_return (C++20) co_yield (C++20) decltype (C++11) default delete	do double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new noexcept (C++11)     not not_eq nullptr (C++11) operator or or_eq private protected public register	reinterpret_cast requires (C++20) return short signed sizeof (*) static static_assert (C++11) static_cast struct switch template this thread_local (C++11) throw true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq
Identifiers with special meaning
final (C++11) import (C++20)	module (C++20) override (C++11)

 

Usage

• long type modifier

Example

Run this code

#include <climits>
#include <concepts>
#include <iostream>
#include <limits>
#include <locale>
 
static_assert(
    sizeof(long) >= 32 / CHAR_BIT &&
    sizeof(unsigned long) >= 32 / CHAR_BIT &&
    std::numeric_limits<long>::min() <= -2'147'483'647l - 1 && //'
    std::numeric_limits<long>::max() >= 2'147'483'647l && //'
    std::numeric_limits<unsigned long>::max() >= 4'294'967'295ul); //'
 
// 'long long' and 'unsigned long long' are available since C++11
static_assert(
    sizeof(long long) >= 64 / CHAR_BIT &&
    sizeof(unsigned long long) >= 64 / CHAR_BIT &&
    std::numeric_limits<long long>::min() <= -9'223'372'036'854'775'807ll - 1 &&
    std::numeric_limits<long long>::max() >= 9'223'372'036'854'775'807ll &&
    std::numeric_limits<unsigned long long>::max() >= 18'446'744'073'709'551'615ull);
 
// concepts are available since C++20
static_assert(
    std::integral<long> &&
    std::integral<long long> &&
    std::integral<unsigned long> &&
    std::integral<unsigned long long> &&
    std::floating_point<long double>);
// Note that 'long' cannot modify 'float'
 
static_assert(
    std::same_as<decltype(0l), signed long int> &&
    std::same_as<decltype(0ll), signed long long int> &&
    std::same_as<decltype(0ul), unsigned long int> &&
    std::same_as<decltype(0ull), unsigned long long int> &&
    std::same_as<decltype(0.l), long double>);
 
template <typename T, typename... Ts>
concept all_same = (... and std::same_as <T, Ts>);
 
static_assert(
    all_same<long, long int, signed long, signed long int> &&
    all_same<unsigned long, unsigned long int> &&
    all_same<long long, long long int, signed long long, signed long long int> &&
    all_same<unsigned long long, unsigned long long int>);
 
#define OUT(...) std::cout << #__VA_ARGS__ << " = " << __VA_ARGS__ << '\n'
 
int main()
{
    std::cout.imbue(std::locale("en_US.UTF-8"));
 
    OUT(sizeof(long));
    OUT(std::numeric_limits<long>::min());
    OUT(std::numeric_limits<long>::max());
    OUT(std::numeric_limits<unsigned long>::max());
 
    OUT(sizeof(long long));
    OUT(std::numeric_limits<long long>::min());
    OUT(std::numeric_limits<long long>::max());
    OUT(std::numeric_limits<unsigned long long>::max());
}
 
#undef OUT

Possible output:

sizeof(long) = 8
std::numeric_limits<long>::min() = -9,223,372,036,854,775,808
std::numeric_limits<long>::max() = 9,223,372,036,854,775,807
std::numeric_limits<unsigned long>::max() = 18,446,744,073,709,551,615
sizeof(long long) = 8
std::numeric_limits<long long>::min() = -9,223,372,036,854,775,808
std::numeric_limits<long long>::max() = 9,223,372,036,854,775,807
std::numeric_limits<unsigned long long>::max() = 18,446,744,073,709,551,615

See also

• Fundamental types: void, std::nullptr_t(since C++11).
  • Integral types: int. Modifiers: signed, unsigned, short, long.
    • Boolean type: bool. Boolean literals: false, true.
    • Character types: char, char8_t(since C++20), char16_t, char32_t(since C++11), wchar_t.
  • Floating-point types: float, double.