---
title: "Built-in types  (C++)"
ms.date: "12/11/2019"
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---
# Built-in types (C++)

Built-in types (also called *fundamental types*) are specified by the C++ language standard and are built into the compiler. Built-in types are not defined in any header file. Built-in types are divided into three categories: integral, floating point, and void. Integral types are capable of handling whole numbers. Floating point types are capable of specifying values that may have fractional parts.

The [void](void-cpp.md) type describes an empty set of values. No variable of type **void** can be specified — it is used primarily to declare functions that return no values or to declare generic pointers to untyped or arbitrarily typed data. Any expression can be explicitly converted or cast to type **void**. However, such expressions are restricted to the following uses:

- An expression statement. (For more information, see [Expressions](expressions-cpp.md).)

- The left operand of the comma operator. (For more information, see [Comma Operator](comma-operator.md).)

- The second or third operand of the conditional operator (`? :`). (For more information, see [Expressions with the Conditional Operator](conditional-operator-q.md).)

The following table explains the restrictions on type sizes in relation to each other. These restrictions are mandated by the C++ standard and are independent of the Microsoft implementation. The absolute size of certain built-in types is not specified in the standard.

### Built-in type size restrictions

|Category|Type|Contents|
|--------------|----------|--------------|
|Integral|**char**|Type **char** is an integral type that usually contains members of the basic execution character set — By default, this is ASCII in Microsoft C++.<br /><br /> The C++ compiler treats variables of type **char**, **signed char**, and **unsigned char** as having different types. Variables of type **char** are promoted to **int** as if they are type **signed char** by default, unless the /J compilation option is used. In this case, they are treated as type **unsigned char** and are promoted to **int** without sign extension.|
||**bool**|Type **bool** is an integral type that can have one of the two values **true** or **false**. Its size is unspecified.|
||**short**|Type **short int** (or simply **short**) is an integral type that is larger than or equal to the size of type **char**, and shorter than or equal to the size of type **int**.<br /><br /> Objects of type **short** can be declared as **signed short** or **unsigned short**. **Signed short** is a synonym for **short**.|
||**int**|Type **int** is an integral type that is larger than or equal to the size of type **short int**, and shorter than or equal to the size of type **long**.<br /><br /> Objects of type **int** can be declared as **signed int** or **unsigned int**. **Signed int** is a synonym for **int**.|
||**__int8**, **__int16**, **__int32**, **__int64**|Sized integer `__int n`, where `n` is the size, in bits, of the integer variable. **__int8**, **__int16**, **__int32** and **__int64** are Microsoft-specific keywords. Not all types are available on all architectures. (**__int128** is not supported.)|
||**long**|Type **long** (or **long int**) is an integral type that is larger than or equal to the size of type **int**. (On Windows **long** is the same size as **int**.)<br /><br /> Objects of type **long** can be declared as **signed long** or **unsigned long**. **Signed long** is a synonym for **long**.|
||**long long**|Larger than an unsigned **long**.<br /><br /> Objects of type **long long** can be declared as **signed long long** or **unsigned long long**. **signed long long** is a synonym for **long long**.|
||**wchar_t**, **__wchar_t**|A variable of type **wchar_t** designates a wide-character or multibyte character type. By default, **wchar_t** is a native type, but you can use [/Zc:wchar_t-](../build/reference/zc-wchar-t-wchar-t-is-native-type.md) to make **wchar_t** a typedef for **unsigned short**. The **__wchar_t** type is a Microsoft-specific synonym for the native **wchar_t** type.<br /><br /> Use the L prefix before a character or string literal to designate the wide-character type.|
|Floating point|**float**|Type **float** is the smallest floating point type.|
||**double**|Type **double** is a floating point type that is larger than or equal to type **float**, but shorter than or equal to the size of type **long double**.<br /><br /> Microsoft-specific: The representation of **long double** and **double** is identical. However, **long double** and **double** are separate types.|
||**long double**|Type **long double** is a floating point type that is larger than or equal to type **double**.|

**Microsoft Specific**

The following table lists the amount of storage required for built-in types in Microsoft C++. In particular, note that **long** is 4 bytes even on 64-bit operating systems.

### Sizes of built-in types

|Type|Size|
|----------|----------|
|**bool**, **char**, **unsigned char**, **signed char**, **__int8**|1 byte|
|**__int16**, **short**, **unsigned short**, **wchar_t**, **__wchar_t**|2 bytes|
|**float**, **__int32**, **int**, **unsigned int**, **long**, **unsigned long**|4 bytes|
|**double**, **__int64**, **long double**, **long long**|8 bytes|

**END Microsoft Specific**

See [Data Type Ranges](data-type-ranges.md) for a summary of the range of values of each type.

For more information about type conversion, see [Standard Conversions](standard-conversions.md).

## See also

[Data Type Ranges](data-type-ranges.md)