NAME
mbrtowc,
mbrtowc_l, mbrtoc16,
mbrtoc16_l, mbrtoc32,
mbrtoc32_l —
convert a character to a wide-character
code (restartable)
LIBRARY
library “libc”
SYNOPSIS
#include
<wchar.h>
size_t
mbrtowc(wchar_t * restrict pc,
const char * restrict s, size_t
n, mbstate_t * restrict ps);
#include
<uchar.h>
size_t
mbrtoc16(char16_t * restrict pc,
const char * restrict s, size_t
n, mbstate_t * restrict ps);
size_t
mbrtoc32(char32_t * restrict pc,
const char * restrict s, size_t
n, mbstate_t * restrict ps);
#include
<xlocale.h>
size_t
mbrtowc_l(wchar_t * restrict pc,
const char * restrict s, size_t
n, mbstate_t * restrict ps,
locale_t locale);
size_t
mbrtoc16_l(char16_t * restrict
pc, const char * restrict s,
size_t n, mbstate_t * restrict
ps, locale_t locale);
size_t
mbrtoc32_l(char32_t * restrict
pc, const char * restrict s,
size_t n, mbstate_t * restrict
ps, locale_t locale);
DESCRIPTION
Thembrtowc(),
mbrtowc_l(), mbrtoc16(),
mbrtoc16_l(),
mbrtoc32(),
and mbrtoc32_l() functions inspect at most
n bytes pointed to by s to
determine the number of bytes needed to complete the next multibyte character.
If a character can be completed, and pc is not
NULL, the wide character which is represented by
s is stored in the wchar_t,
char16_t or char32_t it points to.
If s is NULL, these
functions behave as if pc was
NULL, s was an empty string
("") and n was 1.
The mbstate_t argument,
ps, is used to keep track of the shift state. If it is
NULL, these functions use an internal, static
mbstate_t object, which is initialized to the initial
conversion state at program startup.
As a single char16_t is not
large enough to represent certain multibyte characters, the
mbrtoc16()
function may need to be invoked multiple times to convert a single multibyte
character sequence.
The
mbrtowc_l(),
mbrtoc16_l(),
and
mbrtoc32_l()
functions take an explicit locale argument, whereas
the mbrtowc(), mbrtoc16(),
and mbrtoc32() functions use the current global or
per-thread locale.
RETURN VALUES
The mbrtowc(),
mbrtowc_l(), mbrtoc16(),
mbrtoc16_l(), mbrtoc32(),
and mbrtoc32_l() functions return:
- 0
- The next n or fewer bytes represent the null wide
character (
L'\0'). - >0
- The next n or fewer bytes represent a valid character, these functions return the number of bytes used to complete the multibyte character.
- (size_t)-1
- An encoding error has occurred. The next n or fewer bytes do not contribute to a valid multibyte character.
- (size_t)-2
- The next n contribute to, but do not complete, a valid multibyte character sequence, and all n bytes have been processed.
The mbrtoc16() and
mbrtoc16_l() functions also return:
- (size_t)-3
- The next character resulting from a previous call has been stored. No bytes from the input have been consumed.
ERRORS
The mbrtowc(),
mbrtowc_l(), mbrtoc16(),
mbrtoc16_l(), mbrtoc32(),
and mbrtoc32_l() functions will fail if:
- [
EILSEQ] - An invalid multibyte sequence was detected.
- [
EINVAL] - The conversion state is invalid.
SEE ALSO
mbtowc(3), multibyte(3), setlocale(3), wcrtomb(3), xlocale(3)
STANDARDS
The mbrtowc(),
mbrtoc16() and mbrtoc32()
functions conform to ISO/IEC 9899:2011
(“ISO C11”).