mbsinit - test for initial shift state
#include <wchar.h>
int mbsinit (const mbstate_t *ps);
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, and the one
used by wide character to multibyte conversion functions, such as wcsr-
tombs, 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.
mbsinit returns non-zero if *ps is an initial state, or if ps is a null
pointer. Otherwise it returns 0.
ISO/ANSI C, UNIX98
mbsrtowcs(3), wcsrtombs(3)
The behaviour of mbsinit depends on the LC_CTYPE category of the current
locale.
GNU 2000-11-20 MBSINIT(3)
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