trusty (3) mbsinit.3.gz

NAME

       mbsinit - test for initial shift state

SYNOPSIS

       #include <wchar.h>

       int mbsinit(const mbstate_t *ps);

DESCRIPTION

       Character  conversion  between  the  multibyte  representation and the wide character representation uses
       conversion state, of type mbstate_t.  Conversion of a string uses a  finite-state  machine;  when  it  is
       interrupted  after  the  complete  conversion  of a number of characters, it may need to save a state for
       processing the remaining characters.  Such a conversion state is needed for the sake of encodings such as
       ISO-2022 and UTF-7.

       The initial state is the state at the beginning of conversion of a string.  There are two kinds of state:
       The one used by multibyte to wide character conversion functions, such as mbsrtowcs(3), and the one  used
       by  wide  character  to  multibyte  conversion  functions,  such  as wcsrtombs(3), but they both fit in a
       mbstate_t, and they both have the same representation for an initial state.

       For 8-bit encodings, all states are equivalent to the initial state.  For multibyte encodings like UTF-8,
       EUC-*,  BIG5  or  SJIS,  the  wide  character to multibyte conversion functions never produce non-initial
       states, but the multibyte to wide-character conversion functions like mbrtowc(3) do  produce  non-initial
       states when interrupted in the middle of a character.

       One possible way to create an mbstate_t in initial state is to set it to zero:

           mbstate_t state;
           memset(&state,0,sizeof(mbstate_t));

       On Linux, the following works as well, but might generate compiler warnings:

           mbstate_t state = { 0 };

       The function mbsinit() tests whether *ps corresponds to an initial state.

RETURN VALUE

       mbsinit()  returns  nonzero if *ps is an initial state, or if ps is a NULL pointer.  Otherwise it returns
       0.

ATTRIBUTES

   Multithreading (see pthreads(7))
       The mbsinit() function is thread-safe.

CONFORMING TO

       C99.

NOTES

       The behavior of mbsinit() depends on the LC_CTYPE category of the current locale.

SEE ALSO

       mbsrtowcs(3), wcsrtombs(3)

COLOPHON

       This page is part of release 3.54 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/.