xref: /freebsd/lib/libc/stdio/fgetwln.3 (revision ec994981447e8a974426660b5071bc405280af73)
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28.\"     @(#)fgetln.3	8.3 (Berkeley) 4/19/94
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30.Dd July 16, 2004
31.Dt FGETWLN 3
32.Os
33.Sh NAME
34.Nm fgetwln
35.Nd get a line of wide characters from a stream
36.Sh LIBRARY
37.Lb libc
38.Sh SYNOPSIS
39.In stdio.h
40.In wchar.h
41.Ft wchar_t *
42.Fn fgetwln "FILE * restrict stream" "size_t * restrict len"
43.Sh DESCRIPTION
44The
45.Fn fgetwln
46function
47returns a pointer to the next line from the stream referenced by
48.Fa stream .
49This line is
50.Em not
51a standard wide character string as it does not end with a terminating
52null wide character.
53The length of the line, including the final newline,
54is stored in the memory location to which
55.Fa len
56points.
57(Note, however, that if the line is the last
58in a file that does not end in a newline,
59the returned text will not contain a newline.)
60.Sh RETURN VALUES
61Upon successful completion a pointer is returned;
62this pointer becomes invalid after the next
63.Tn I/O
64operation on
65.Fa stream
66(whether successful or not)
67or as soon as the stream is closed.
68Otherwise,
69.Dv NULL
70is returned.
71The
72.Fn fgetwln
73function
74does not distinguish between end-of-file and error; the routines
75.Xr feof 3
76and
77.Xr ferror 3
78must be used
79to determine which occurred.
80If an error occurs, the global variable
81.Va errno
82is set to indicate the error.
83The end-of-file condition is remembered, even on a terminal, and all
84subsequent attempts to read will return
85.Dv NULL
86until the condition is
87cleared with
88.Xr clearerr 3 .
89.Pp
90The text to which the returned pointer points may be modified,
91provided that no changes are made beyond the returned size.
92These changes are lost as soon as the pointer becomes invalid.
93.Sh ERRORS
94.Bl -tag -width Er
95.It Bq Er EBADF
96The argument
97.Fa stream
98is not a stream open for reading.
99.El
100.Pp
101The
102.Fn fgetwln
103function
104may also fail and set
105.Va errno
106for any of the errors specified for the routines
107.Xr mbrtowc 3 ,
108.Xr realloc 3 ,
109or
110.Xr read 2 .
111.Sh SEE ALSO
112.Xr ferror 3 ,
113.Xr fgetln 3 ,
114.Xr fgetws 3 ,
115.Xr fopen 3
116