freebsd-dev/lib/libc/locale/mbsrtowcs.3

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.\" Copyright (c) 2002 Tim J. Robbins
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.Dd August 16, 2002
.Dt MBSRTOWCS 3
.Os
.Sh NAME
.Nm mbsrtowcs
.Nd "convert a character string to a wide-character string (restartable)"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In wchar.h
.Ft size_t
.Fn mbsrtowcs "wchar_t * restrict dst" "const char ** restrict src" "size_t len" "mbstate_t * restrict ps"
.Sh DESCRIPTION
The
.Fn mbsrtowcs
function converts a sequence of multibyte characters pointed to indirectly by
.Fa src
into a sequence of corresponding wide characters and stores at most
.Fa len
of them in the
.Ft wchar_t
array pointed to by
.Fa dst ,
until it encounters a terminating null character ('\e0').
.Pp
If
.Fa dst
is
.Dv NULL ,
no characters are stored.
.Pp
If
.Fa dst
is not
.Dv NULL ,
the pointer pointed to by
.Fa src
is updated to point to the character after the one that conversion stopped at.
If conversion stops because a null character is encountered,
.No * Ns Fa src
is set to
.Dv NULL .
.Pp
The
.Ft mbstate_t
argument,
.Fa ps ,
is used to keep track of the shift state.
If it is
.Dv NULL ,
.Fn mbsrtowcs
uses an internal, static
.Ft mbstate_t
object.
.Sh RETURN VALUES
The
.Fn mbsrtowcs
function returns the number of wide characters stored in
the array pointed to by
.Fa dst
if successful, otherwise it returns
.No ( Ns
.Ft size_t Ns
.No ) Ns -1 .
.Sh ERRORS
The
.Fn mbsrtowcs
function will fail if:
.Bl -tag -width Er
.It Bq Er EILSEQ
An invalid multibyte character sequence was encountered.
.El
.Sh SEE ALSO
.Xr mbrtowc 3 ,
.Xr mbstowcs 3 ,
.Xr wcsrtombs 3
.Sh STANDARDS
The
.Fn mbsrtowcs
function conforms to
.St -isoC-99 .
.Sh BUGS
The current implementation does not support shift states.