libc/stdio/fgetws.3

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.\"     @(#)fgets.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: head/lib/libc/stdio/fgetws.3 165903 2007-01-09 00:28:16Z imp $
.\"
.Dd December 26, 2013
.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 *"
.Fn fgetws "wchar_t * restrict ws" "int n" "FILE * restrict fp"
.In xlocale.h
.Ft "wchar_t *"
.Fn fgetws_l "wchar_t * restrict ws" "int n" "FILE * restrict fp" "locale_t locale"
.Sh DESCRIPTION
The
.Fn fgetws
and
.Fn fgetws_l
functions read at most one less than the number of characters specified by
.Fa n
from the given
.Fa fp
and store 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
The
.Fn fgetws_l
function takes an explicit
.Fa locale
argument, whereas the
.Fn fgetws
function uses the current global or per-thread locale.
.Sh RETURN VALUES
Upon successful completion,
.Fn fgetws
and
.Fn fgetws_l
return
.Fa ws .
If end-of-file occurs before any characters are read,
.Fn fgetws
and
.Fn fgetws_l
return
.Dv NULL
and the buffer contents remain unchanged.
If an error occurs,
.Fn fgetws
and
.Fn fgetws_l
return
.Dv NULL
and the buffer contents are indeterminate.
The
.Fn fgetws
and
.Fn fgetws_l
functions
do not distinguish between end-of-file and error, and callers must use
.Xr feof 3
and
.Xr ferror 3
to determine which occurred.
.Sh ERRORS
The
.Fn fgetws
and
.Fn fgetws_l
functions will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
The given
.Fa fp
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 functions
.Fn fgetws
and
.Fn fgetws_l
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 .