# Header boost/cstdint.hpp

The header `<boost/cstdint.hpp>` provides the typedef's useful for writing portable code that requires certain integer widths. All typedef's are in namespace boost.

The specifications are based on the ISO/IEC 9899:1999 C Language standard header <stdint.h>. The 64-bit types required by the C standard are not required in the boost header, and may not be supplied in all implementations, because `long long` is not [yet] included in the C++ standard.

See cstdint_test.cpp for a test program.

## Exact-width integer types

The typedef `int#_t`, with # replaced by the width, designates a signed integer type of exactly # bits; `int8_t` denotes an 8-bit signed integer type. Similarly, the typedef `uint#_t` designates and unsigned integer type of exactly # bits.

These types are optional. However, if an implementation provides integer types with widths of 8, 16, 32, or 64 bits, it shall define the corresponding typedef names.

## Minimum-width integer types

The typedef `int_least#_t`, with # replaced by the width, designates a signed integer type with a width of at least # bits, such that no signed integer type with lesser size has at least the specified width. Thus, `int_least32_t` denotes a signed integer type with a width of at least 32 bits. Similarly, the typedef name `uint_least#_t` designates an unsigned integer type with a width of at least # bits, such that no unsigned integer type with lesser size has at least the specified width.

Required minimum-width integer types:

- `int_least8_t`
- `int_least16_t`
- `int_least32_t`
- `uint_least8_t`
- `uint_least16_t`
- `uint_least32_t`

All other minimum-width integer types are optional.

## Fastest minimum-width integer types

The typedef `int_fast#_t`, with # replaced by the width, designates the fastest signed integer type with a width of at least # bits. Similarly, the typedef name `uint_fast#_t` designates the fastest unsigned integer type with a width of at least # bits.

There is no guarantee that these types are fastest for all purposes. In any case, however, they satisfy the signedness and width requirements.

Required fastest minimum-width integer types:

- `int_fast8_t`
- `int_fast16_t`
- `int_fast32_t`
- `uint_fast8_t`
- `uint_fast16_t`
- `uint_fast32_t`

All other fastest minimum-width integer types are optional.

## Greatest-width integer types

The typedef `intmax_t` designates a signed integer type capable of representing any value of any signed integer type.

The typedef `uintmax_t` designates an unsigned integer type capable of representing any value of any unsigned integer type.

These types are required.

Revised 19 Aug 2001