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

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