mbsinit(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

MBSINIT(3)              Linux Programmer's Manual             MBSINIT(3)

NAME         top

       mbsinit - test for initial shift state

SYNOPSIS         top

       #include <wchar.h>

       int mbsinit(const mbstate_t *ps);

DESCRIPTION         top

       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(state));

       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         top

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

ATTRIBUTES         top

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

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             Attribute     Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │mbsinit()                             │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO         top

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

NOTES         top

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

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 5.12 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

GNU                            2021-03-22                     MBSINIT(3)

Pages that refer to this page: mbrtowc(3)mbsnrtowcs(3)mbsrtowcs(3)wcrtomb(3)wcsnrtombs(3)wcsrtombs(3)