mbsinit(3)

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 NULL.
   Otherwise, it returns 0.

ATTRIBUTES

   For   an   explanation   of   the  terms  used  in  this  section,  see
   attributes(7).

   
   Interface  Attribute      Value   
   
   mbsinit()  Thread safety  MT-Safe 
   

CONFORMING TO

   POSIX.1-2001, POSIX.1-2008, C99.

NOTES

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

SEE ALSO

   mbrlen(3), mbrtowc(3), mbsrtowcs(3), wcrtomb(3), wcsrtombs(3)

COLOPHON

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