freebsd-dev/share/man/man7/stdint.7

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.Dd September 15, 2002
.Dt STDINT 7
.Os
.Sh NAME
.Nm stdint
.Nd "standard integer types"
.Sh SYNOPSIS
.In stdint.h
.Sh DESCRIPTION
The
.In stdint.h
header provides source-portable integer types of a specific
size, smallest memory footprint with a minimum size, fastest
access speed with a minimum size, largest integer size, and
those capable of storing pointers.
.Pp
The types
.Vt int8_t ,
.Vt int16_t ,
.Vt int32_t ,
and
.Vt int64_t
provide a signed integer type of width 8, 16, 32, or 64 bits, respectively.
The types
.Vt uint8_t ,
.Vt uint16_t ,
.Vt uint32_t ,
and
.Vt uint64_t
provide an unsigned integer type of width 8, 16, 32, or 64 bits, respectively.
These integer types should be used when a specific size is required.
.Pp
The types
.Vt int_fast8_t ,
.Vt int_fast16_t ,
.Vt int_fast32_t ,
and
.Vt int_fast64_t
provide the fastest signed integer type with a width
of at least 8, 16, 32, or 64 bits, respectively.
The types
.Vt uint_fast8_t ,
.Vt uint_fast16_t ,
.Vt uint_fast32_t ,
and
.Vt uint_fast64_t
provide the fastest unsigned integer type with a width
of at least 8, 16, 32, or 64 bits, respectively.
These types should be used when access speed is
paramount, and when a specific size is not required.
.Pp
The types
.Vt int_least8_t ,
.Vt int_least16_t ,
.Vt int_least32_t ,
and
.Vt int_least64_t
provide the smallest memory footprint signed integer type with
a width of at least 8, 16, 32, or 64 bits, respectively.
The types
.Vt uint_least8_t ,
.Vt uint_least16_t ,
.Vt uint_least32_t ,
and
.Vt uint_least64_t
provide the smallest memory footprint unsigned integer type with
a width of at least 8, 16, 32, or 64 bits, respectively.
These types should be used when memory storage is of
concern, and when a specific size is not required.
.Pp
The type
.Vt intmax_t
provides a signed integer type large
enough to hold any other signed integer.
The type
.Vt uintmax_t
provides an unsigned integer type large
enough to hold any other unsigned integer.
These types are generally the largest signed and unsigned
integer types available on a specific architecture.
.Pp
The type
.Vt intptr_t
provides a signed integer type with the ability to hold a pointer to
.Vt void ,
that can later be converted back to a pointer to
.Vt void .
.Pp
The type
.Vt uintptr_t
provides an unsigned integer type with the ability to hold a pointer to
.Vt void ,
that can later be converted back to a pointer to
.Vt void .
.Pp
Additionally, the
.In stdint.h
header defines some macros, but none of them are documented here.
.Sh STANDARDS
The
.In stdint.h
header conforms to
.St -isoC-99
and
.St -p1003.1-2001 .
.Sh HISTORY
The
.In stdint.h
header was first introduced in
.Fx 5.0 .