Updated: 2025/Nov/16

Please read Privacy Policy. It's for your privacy.

UCHAR(3)                   Library Functions Manual                   UCHAR(3)

NAME
     uchar - Unicode utilities

SYNOPSIS
     #include <uchar.h>

DESCRIPTION
     The <uchar.h> header file declares types and functions for manipulating
     Unicode code units.

   Types
     char8_t       (C23) Unsigned integer type for UTF-8 code units.

                   Same type as unsigned char.

     char16_t      Unsigned integer type for UTF-16 code units.

                   Same type as uint_least16_t from <stdint.h>.  May represent
                   both surrogate code points, i.e., code points in the
                   interval [0xd800,0xdfff], and Unicode scalar values in the
                   Basic Multilingual Plane, which are the 16-bit code points
                   other than surrogate code points.

     char32_t      Unsigned integer type for UTF-32 code units.

                   Same type as uint_least32_t from <stdint.h>.  Can represent
                   all Unicode scalar values, not just those in the Basic
                   Multilingual Plane.  Intended to represent only Unicode
                   scalar values, not surrogate code points.

     mbstate_t     Opaque multibyte conversion state.

                   Same type as in stddef.h and wchar.h.

     size_t        Unsigned integer type to represent array sizes.

                   Same type as in stddef.h, stdint.h, and sys/types.h.

   Functions
     The <uchar.h> header file declares the functions mbrtoc8(3), c8rtomb(3),
     mbrtoc16(3), c16rtomb(3), mbrtoc32(3), and c32rtomb(3) for conversion
     between multibyte sequences and UTF-8/UTF-16/UTF-32 code units.

SEE ALSO
     c8rtomb(3), c16rtomb(3), c32rtomb(3), mbrtoc8(3), mbrtoc16(3),
     mbrtoc32(3)

     The Unicode Standard,
     https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf,
     The Unicode Consortium, September 2022, Version 15.0 -- Core
     Specification.

     P. Hoffman and F. Yergeau, UTF-16, an encoding of ISO 10646, Internet
     Engineering Task Force, RFC 2781,
     https://datatracker.ietf.org/doc/html/rfc2781, February 2000.

     F. Yergeau, UTF-8, a transformation format of ISO 10646, Internet
     Engineering Task Force, RFC 3629,
     https://datatracker.ietf.org/doc/html/rfc3629, November 2003.

STANDARDS
     The <uchar.h> header file conforms to ISO/IEC 9899:2011 ("ISO C11") and
     IEEE Std 1003.1-2024 ("POSIX.1").

HISTORY
     The <uchar.h> header file first appeared in NetBSD 11.0.

NetBSD 11.99                    August 15, 2024                   NetBSD 11.99