xref: /freebsd/lib/libc/stdio/fgetwln.3 (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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28.\"     @(#)fgetln.3	8.3 (Berkeley) 4/19/94
29.\" $FreeBSD$
30.\"
31.Dd July 16, 2004
32.Dt FGETWLN 3
33.Os
34.Sh NAME
35.Nm fgetwln
36.Nd get a line of wide characters from a stream
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In stdio.h
41.In wchar.h
42.Ft wchar_t *
43.Fn fgetwln "FILE * restrict stream" "size_t * restrict len"
44.Sh DESCRIPTION
45The
46.Fn fgetwln
47function
48returns a pointer to the next line from the stream referenced by
49.Fa stream .
50This line is
51.Em not
52a standard wide character string as it does not end with a terminating
53null wide character.
54The length of the line, including the final newline,
55is stored in the memory location to which
56.Fa len
57points.
58(Note, however, that if the line is the last
59in a file that does not end in a newline,
60the returned text will not contain a newline.)
61.Sh RETURN VALUES
62Upon successful completion a pointer is returned;
63this pointer becomes invalid after the next
64.Tn I/O
65operation on
66.Fa stream
67(whether successful or not)
68or as soon as the stream is closed.
69Otherwise,
70.Dv NULL
71is returned.
72The
73.Fn fgetwln
74function
75does not distinguish between end-of-file and error; the routines
76.Xr feof 3
77and
78.Xr ferror 3
79must be used
80to determine which occurred.
81If an error occurs, the global variable
82.Va errno
83is set to indicate the error.
84The end-of-file condition is remembered, even on a terminal, and all
85subsequent attempts to read will return
86.Dv NULL
87until the condition is
88cleared with
89.Xr clearerr 3 .
90.Pp
91The text to which the returned pointer points may be modified,
92provided that no changes are made beyond the returned size.
93These changes are lost as soon as the pointer becomes invalid.
94.Sh ERRORS
95.Bl -tag -width Er
96.It Bq Er EBADF
97The argument
98.Fa stream
99is not a stream open for reading.
100.El
101.Pp
102The
103.Fn fgetwln
104function
105may also fail and set
106.Va errno
107for any of the errors specified for the routines
108.Xr mbrtowc 3 ,
109.Xr realloc 3 ,
110or
111.Xr read 2 .
112.Sh SEE ALSO
113.Xr ferror 3 ,
114.Xr fgetln 3 ,
115.Xr fgetws 3 ,
116.Xr fopen 3
117