mbsinit

MBSINIT(3)		  Linux Programmer’s Manual		   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 inter-
       rupted 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, and the one
       used by wide character to  multibyte  conversion	 functions,  such  as
       wcsrtombs,  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 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 non-zero if *ps is an initial state, or	if  ps	is  a
       null pointer. Otherwise it returns 0.

CONFORMING TO
       ISO/ANSI C, UNIX98

SEE ALSO
       mbsrtowcs(3), wcsrtombs(3)

NOTES
       The  behaviour of mbsinit depends on the LC_CTYPE category of the cur-
       rent locale.



GNU				  2000-11-20			   MBSINIT(3)