.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH intN_t 3type 2025-10-29 "Linux man-pages 6.16"
.SH NAME
intN_t, int8_t, int16_t, int32_t, int64_t,
uintN_t, uint8_t, uint16_t, uint32_t, uint64_t
\- fixed-width basic integer types
.SH LIBRARY
Standard C library
.RI ( libc )
.SH SYNOPSIS
.nf
.B #include <stdint.h>
.P
.BR typedef " /* ... */ " int8_t;
.BR typedef " /* ... */ " int16_t;
.BR typedef " /* ... */ " int32_t;
.BR typedef " /* ... */ " int64_t;
.P
.BR typedef " /* ... */ " uint8_t;
.BR typedef " /* ... */ " uint16_t;
.BR typedef " /* ... */ " uint32_t;
.BR typedef " /* ... */ " uint64_t;
.P
.B "#define INT8_WIDTH   8"
.B "#define INT16_WIDTH  16"
.B "#define INT32_WIDTH  32"
.B "#define INT64_WIDTH  64"
.P
.B "#define UINT8_WIDTH  8"
.B "#define UINT16_WIDTH 16"
.B "#define UINT32_WIDTH 32"
.B "#define UINT64_WIDTH 64"
.P
.BR "#define INT8_MAX     " "/*  2**(INT8_WIDTH - 1) - 1   */"
.BR "#define INT16_MAX    " "/*  2**(INT16_WIDTH - 1) - 1  */"
.BR "#define INT32_MAX    " "/*  2**(INT32_WIDTH - 1) - 1  */"
.BR "#define INT64_MAX    " "/*  2**(INT64_WIDTH - 1) - 1  */"
.P
.BR "#define INT8_MIN     " "/*  - 2**(INT8_WIDTH - 1)     */"
.BR "#define INT16_MIN    " "/*  - 2**(INT16_WIDTH - 1)    */"
.BR "#define INT32_MIN    " "/*  - 2**(INT32_WIDTH - 1)    */"
.BR "#define INT64_MIN    " "/*  - 2**(INT64_WIDTH - 1)    */"
.P
.BR "#define UINT8_MAX    " "/*  2**INT8_WIDTH - 1         */"
.BR "#define UINT16_MAX   " "/*  2**INT16_WIDTH - 1        */"
.BR "#define UINT32_MAX   " "/*  2**INT32_WIDTH - 1        */"
.BR "#define UINT64_MAX   " "/*  2**INT64_WIDTH - 1        */"
.P
.BI "#define INT8_C(" c ")    " c " ## " "\f[R]/* ... */\f[]"
.BI "#define INT16_C(" c ")   " c " ## " "\f[R]/* ... */\f[]"
.BI "#define INT32_C(" c ")   " c " ## " "\f[R]/* ... */\f[]"
.BI "#define INT64_C(" c ")   " c " ## " "\f[R]/* ... */\f[]"
.P
.BI "#define UINT8_C(" c ")   " c " ## " "\f[R]/* ... */\f[]"
.BI "#define UINT16_C(" c ")  " c " ## " "\f[R]/* ... */\f[]"
.BI "#define UINT32_C(" c ")  " c " ## " "\f[R]/* ... */\f[]"
.BI "#define UINT64_C(" c ")  " c " ## " "\f[R]/* ... */\f[]"
.fi
.SH DESCRIPTION
.IR int N _t
are
signed integer types
of a fixed width of exactly N bits,
.I N
being the value specified in its type name.
They are be capable of storing values in the range
.RB [ INT \f[I]N\f[] _MIN ,
.BR INT \f[I]N\f[] _MAX ],
substituting
.I N
by the appropriate number.
.P
.IR uint N _t
are
unsigned integer types
of a fixed width of exactly N bits,
N being the value specified in its type name.
They are capable of storing values in the range
.RB [ 0 ,
.BR UINT \f[I]N\f[] _MAX ],
substituting
.I N
by the appropriate number.
.P
According to POSIX,
.RI [ u ] int8_t ,
.RI [ u ] int16_t ,
and
.RI [ u ] int32_t
are required;
.RI [ u ] int64_t
are only required in implementations that provide integer types with width 64;
and all other types of this form are optional.
.P
The macros
.RB [ U ] INT \f[I]N\f[] _WIDTH
expand to the width in bits of these types
.RI ( N ).
.P
The macros
.RB [ U ] INT \f[I]N\f[] _MAX
expand to the maximum value that these types can hold.
.P
The macros
.BI INT N _MIN
expand to the minimum value that these types can hold.
.P
The macros
.RB [ U ] INT \f[I]N\f[] _C ()
expand their argument to an integer constant of type
.RI [ u ] int N _t .
.P
The length modifiers for the
.RI [ u ] int N _t
types for the
.BR printf (3)
family of functions
are expanded by macros of the forms
.BR PRId \f[I]N\f[],
.BR PRIi \f[I]N\f[],
.BR PRIu \f[I]N\f[],
and
.BI PRIx N
(defined in
.IR <inttypes.h> );
resulting for example in
.B %"PRId64"
or
.B %"PRIi64"
for printing
.I int64_t
values.
The length modifiers for the
.RI [ u ] int N _t
types for the
.BR scanf (3)
family of functions
are expanded by macros of the forms
.BR SCNd \f[I]N\f[],
.BR SCNi \f[I]N\f[],
.BR SCNu \f[I]N\f[],
and
.BI SCNx N,
(defined in
.IR <inttypes.h> );
resulting for example in
.B %"SCNu8"
or
.B %"SCNx8"
for scanning
.I uint8_t
values.
.SH STANDARDS
C11, POSIX.1-2024.
.SH HISTORY
C99, POSIX.1-2001.
.P
The
.RB [ U ] INT \f[I]N\f[] _WIDTH
macros were added in C23.
.SH NOTES
The following header also provides these types:
.IR <inttypes.h> .
.I <arpa/inet.h>
also provides
.I uint16_t
and
.IR uint32_t .
.SH SEE ALSO
.BR intmax_t (3type),
.BR intptr_t (3type),
.BR printf (3)