xref: /freebsd/lib/libc/stdio/fgetwln.3 (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
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28.Dd July 16, 2004
29.Dt FGETWLN 3
30.Os
31.Sh NAME
32.Nm fgetwln
33.Nd get a line of wide characters from a stream
34.Sh LIBRARY
35.Lb libc
36.Sh SYNOPSIS
37.In stdio.h
38.In wchar.h
39.Ft wchar_t *
40.Fn fgetwln "FILE * restrict stream" "size_t * restrict len"
41.Sh DESCRIPTION
42The
43.Fn fgetwln
44function
45returns a pointer to the next line from the stream referenced by
46.Fa stream .
47This line is
48.Em not
49a standard wide character string as it does not end with a terminating
50null wide character.
51The length of the line, including the final newline,
52is stored in the memory location to which
53.Fa len
54points.
55(Note, however, that if the line is the last
56in a file that does not end in a newline,
57the returned text will not contain a newline.)
58.Sh RETURN VALUES
59Upon successful completion a pointer is returned;
60this pointer becomes invalid after the next
61.Tn I/O
62operation on
63.Fa stream
64(whether successful or not)
65or as soon as the stream is closed.
66Otherwise,
67.Dv NULL
68is returned.
69The
70.Fn fgetwln
71function
72does not distinguish between end-of-file and error; the routines
73.Xr feof 3
74and
75.Xr ferror 3
76must be used
77to determine which occurred.
78If an error occurs, the global variable
79.Va errno
80is set to indicate the error.
81The end-of-file condition is remembered, even on a terminal, and all
82subsequent attempts to read will return
83.Dv NULL
84until the condition is
85cleared with
86.Xr clearerr 3 .
87.Pp
88The text to which the returned pointer points may be modified,
89provided that no changes are made beyond the returned size.
90These changes are lost as soon as the pointer becomes invalid.
91.Sh ERRORS
92.Bl -tag -width Er
93.It Bq Er EBADF
94The argument
95.Fa stream
96is not a stream open for reading.
97.El
98.Pp
99The
100.Fn fgetwln
101function
102may also fail and set
103.Va errno
104for any of the errors specified for the routines
105.Xr mbrtowc 3 ,
106.Xr realloc 3 ,
107or
108.Xr read 2 .
109.Sh SEE ALSO
110.Xr ferror 3 ,
111.Xr fgetln 3 ,
112.Xr fgetws 3 ,
113.Xr fopen 3
114