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, converts it to a wide character and stores it at
*pwc.
It updates an internal shift state only known to the mbtowc
function.
If s does not point to a aq\0aq 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 multibyte sequence,
mbtowc()
returns -1.
This can happen even if n >= MB_CUR_MAX,
if the multibyte string contains redundant shift sequences.
A different case is when s is not NULL but pwc is NULL.
#include <this>
case the
mbtowc()
function behaves as above, except 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 nontrivial 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 nontrivial shift state, or zero if the encoding is stateless.
CONFORMING TO
C99.
NOTES
The behavior of
mbtowc()
depends on the
LC_CTYPE
category of the
current locale.
This function is not multithread safe.
The function
mbrtowc(3)
provides
a better interface to the same functionality.
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
