MBRTOWC(3C)MBRTOWC(3C)NAMEmbrtowc - convert a character to a wide-character code (restartable)
SYNOPSIS
#include <wchar.h>
size_t mbrtowc(wchar_t *restrict pwc, const char *restrict s, size_t n,
mbstate_t *restrict ps);
DESCRIPTION
If s is a null pointer, the mbrtowc() function is equivalent to the
call:
mbrtowc(NULL, ``'', 1, ps)
In this case, the values of the arguments pwc and n are ignored.
If s is not a null pointer, the mbrtowc() function inspects at most n
bytes beginning at the byte pointed to by s to determine the number of
bytes needed to complete the next character (including any shift
sequences). If the function determines that the next character is com‐
pleted, it determines the value of the corresponding wide-character and
then, if pwc is not a null pointer, stores that value in the object
pointed to by pwc. If the corresponding wide-character is the null
wide-character, the resulting state described is the initial conversion
state.
If ps is a null pointer, the mbrtowc() function uses its own internal
mbstate_t object, which is initialized at program startup to the ini‐
tial conversion state. Otherwise, the mbstate_t object pointed to by
ps is used to completely describe the current conversion state of the
associated character sequence. Solaris will behave as if no function
defined in the Solaris Reference Manual calls mbrtowc().
The behavior of this function is affected by the LC_CTYPE category of
the current locale. See environ(5).
RETURN VALUES
The mbrtowc() function returns the first of the following that applies:
0
If the next n or fewer bytes complete the character
that corresponds to the null wide-character (which is
the value stored).
positive
If the next n or fewer bytes complete a valid charac‐
ter (which is the value stored); the value returned is
the number of bytes that complete the character.
(size_t)−2
If the next n bytes contribute to an incomplete but
potentially valid character, and all n bytes have been
processed (no value is stored). When n has at least
the value of the MB_CUR_MAX macro, this case can only
occur if s points at a sequence of redundant shift
sequences (for implementations with state-dependent
encodings).
(size_t)−1
If an encoding error occurs, in which case the next n
or fewer bytes do not contribute to a complete and
valid character (no value is stored). In this case,
EILSEQ is stored in errno and the conversion state is
undefined.
ERRORS
The mbrtowc() function may fail if:
EINVAL
The ps argument points to an object that contains an invalid
conversion state.
EILSEQ
Invalid character sequence is detected.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ See NOTES below │
└────────────────────┴─────────────────┘
SEE ALSOmbsinit(3C), setlocale(3C), attributes(5), environ(5), standards(5)NOTES
If ps is not a null pointer, mbrtowc() uses the mbstate_t object
pointed to by ps and the function can be used safely in multithreaded
applications, as long as setlocale(3C) is not being called to change
the locale. If ps is a null pointer, mbrtowc() uses its internal
mbstate_t object and the function is Unsafe in multithreaded applica‐
tions.
Nov 1, 2003 MBRTOWC(3C)
