MBTOWC(3) Linux Programmer's Manual MBTOWC(3)
NAME
mbtowc - convert a multibyte sequence to a wide character
SYNOPSIS
#include <stdlib.h>
int mbtowc (wchar_t *pwc, const char *s, size_t n);
DESCRIPTION
The main case for this function is when s is not NULL and
pwc is not NULL. In this case, the mbtowc function
inspects at most n bytes of the multibyte string starting
at s, extracts the next complete multibyte character, con-
verts it to a wide character and stores it at *pwc. It
updates an internal shift state only known to the mbtowc
function. It s does not point to a '\0' byte, it returns
the number of bytes that were consumed from s, otherwise
it returns 0.
If the n bytes starting at s do not contain a complete
multibyte character, or if they contain an invalid multi-
byte sequence, mbtowc returns -1. This can happen even if
n >= MB_CUR_MAX, if the multibyte string contains redun-
dant shift sequences.
A different case is when s is not NULL but pwc is NULL. In
this case the mbtowc function behaves as above, excepts
that it does not store the converted wide character in
memory.
A third case is when s is NULL. In this case, pwc and n
are ignored. The mbtowc function resets the shift state,
only known to this function, to the initial state, and
returns non-zero if the encoding has non-trivial shift
state, or zero if the encoding is stateless.
RETURN VALUE
If s is not NULL, the mbtowc function returns the number
of consumed bytes starting at s, or 0 if s points to a
null byte, or -1 upon failure.
If s is NULL, the mbtowc function returns non-zero if the
encoding has non-trivial shift state, or zero if the
encoding is stateless.
CONFORMING TO
ISO/ANSI C, UNIX98
SEE ALSO
mbrtowc(3), mbstowcs(3), MB_CUR_MAX(3)
NOTES
The behaviour of mbtowc depends on the LC_CTYPE category
of the current locale.
GNU July 25, 1999 1
MBTOWC(3) Linux Programmer's Manual MBTOWC(3)
This function is not multi-thread safe. The function mbr-
towc provides a better interface to the same functional-
ity.
GNU July 25, 1999 2