Libc-1439.100.3.tar.gz

[apple/libc.git] / stdio / FreeBSD / fgetws.3

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.\"     @(#)fgets.3	8.1 (Berkeley) 6/4/93
.\" FreeBSD: src/lib/libc/stdio/fgets.3,v 1.16 2002/05/31 05:01:17 archie Exp
.\" $FreeBSD: src/lib/libc/stdio/fgetws.3,v 1.4 2007/01/09 00:28:06 imp Exp $
.\"
.Dd August 6, 2002
.Dt FGETWS 3
.Os
.Sh NAME
.Nm fgetws ,
.Nm fgetws_l
.Nd get a line of wide characters from a stream
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdio.h
.In wchar.h
.Ft "wchar_t *"
.Fo fgetws
.Fa "wchar_t *restrict ws"
.Fa "int n"
.Fa "FILE *restrict stream"
.Fc
.In stdio.h
.In wchar.h
.In xlocale.h
.Ft "wchar_t *"
.Fo fgetws_l
.Fa "wchar_t *restrict ws"
.Fa "int n"
.Fa "FILE *restrict stream"
.Fa "locale_t loc"
.Fc
.Sh DESCRIPTION
The
.Fn fgetws
function
reads at most one less than the number of characters specified by
.Fa n
from the given
.Fa stream
and stores them in the wide character string
.Fa ws .
Reading stops when a newline character is found,
at end-of-file or error.
The newline, if any, is retained.
If any characters are read and there is no error, a
.Ql \e0
character is appended to end the string.
.Pp
While the
.Fn fgetws
function uses the current locale, the
.Fn fgetws_l
function may be passed a locale directly. See
.Xr xlocale 3
for more information.
.Sh RETURN VALUES
Upon successful completion,
.Fn fgetws
returns
.Fa ws .
If end-of-file occurs before any characters are read,
.Fn fgetws
returns
.Dv NULL
and the buffer contents remain unchanged.
If an error occurs,
.Fn fgetws
returns
.Dv NULL
and the buffer contents are indeterminate.
The
.Fn fgetws
function
does not distinguish between end-of-file and error;
callers must use
.Xr feof 3
and
.Xr ferror 3
to determine which occurred.
.Sh ERRORS
The
.Fn fgetws
function will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
The given
.Fa stream
argument is not a readable stream.
.It Bq Er EILSEQ
The data obtained from the input stream does not form a valid
multibyte character.
.El
.Pp
The function
.Fn fgetws
may also fail and set
.Va errno
for any of the errors specified for the routines
.Xr fflush 3 ,
.Xr fstat 2 ,
.Xr read 2 ,
or
.Xr malloc 3 .
.Sh SEE ALSO
.Xr feof 3 ,
.Xr ferror 3 ,
.Xr fgets 3 ,
.Xr xlocale 3
.Sh STANDARDS
The
.Fn fgetws
function
conforms to
.St -p1003.1-2001 .