xref: /netbsd-src/lib/libc/stdio/getdelim.3 (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1.\"     $NetBSD: getdelim.3,v 1.7 2009/12/09 18:06:08 joerg Exp $
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6.\" This code is derived from software contributed to The NetBSD Foundation
7.\" by Roy Marples.
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30.Dd November 30, 2009
31.Dt GETDELIM 3
32.Os
33.Sh NAME
34.Nm getdelim ,
35.Nm getline
36.Nd read a delimited record from a stream
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In stdio.h
41.Ft ssize_t
42.Fn getdelim "char ** restrict lineptr" "size_t * restrict n" "int delimiter" "FILE * restrict stream"
43.Ft ssize_t
44.Fn getline "char ** restrict lineptr" "size_t * restrict n" "FILE * restrict stream"
45.Sh DESCRIPTION
46The
47.Fn getdelim
48function reads from the
49.Fa stream
50until it encounters a character matching the
51.Fa delimiter
52character, storing the input in
53.Fa *lineptr .
54The buffer is
55.Dv NUL Ns No -terminated
56and includes the delimiter.
57.Pp
58If
59.Fa *n
60is non-zero, then
61.Fa *lineptr
62must be pre-allocated to at least
63.Fa *n
64bytes.
65.Fn getdelim
66ensures that
67.Fa *lineptr
68is large enough to hold the input, updating
69.Fa *n
70to reflect the new size.
71.Pp
72.Fa delimiter
73must be representable as an unsigned char, and
74.Fa *lineptr
75must be a
76.Xr free 3 Ns No able
77buffer.
78.Pp
79.Fa getline
80is equivalent to
81.Fa getdelim
82with the delimiter set to the newline character.
83.Sh RETURN VALUES
84The
85.Fn getdelim
86and
87.Fn getline
88functions return the number of characters read, including the delimiter.
89If no characters were read and the stream is at end-of-file, the functions
90return \-1.
91If an error occurs, the functions return \-1 and the global variable
92.Va errno
93is set to indicate the error.
94.Pp
95The functions do not distinguish between end-of-file and error,
96and callers must use
97.Xr feof 3
98and
99.Xr ferror 3
100to determine which occurred.
101.Sh EXAMPLES
102The following code fragment reads lines from a file and writes them to
103standard output.
104.Bd -literal -offset indent
105char *line = NULL;
106size_t linesize = 0;
107ssize_t linelen;
108while ((linelen = getline(\*[Am]line, \*[Am]linesize, fp)) != -1)
109	fwrite(line, linelen, 1, stdout);
110
111if (ferror(fp))
112	perror("getline");
113.Ed
114.Sh ERRORS
115.Bl -tag -width [EOVERFLOW]
116.It Bq Er EINVAL
117.Fa *lineptr
118or
119.Fa *n
120is a
121.Dv NULL
122pointer.
123.It Bq Er EOVERFLOW
124More than SSIZE_MAX characters were read without encountering the delimiter.
125.El
126.Pp
127The
128.Fn getdelim
129and
130.Fn getline
131functions may also fail and set
132.Va errno
133for any of the errors specified in the routines
134.Xr fflush 3 ,
135.Xr malloc 3 ,
136.Xr read 2 ,
137.Xr stat 2 ,
138or
139.Xr realloc 3 .
140.Sh SEE ALSO
141.Xr ferror 3 ,
142.Xr fgets 3 ,
143.Xr fopen 3
144.Sh STANDARDS
145The
146.Fn getdelim
147and
148.Fn getline
149functions conform to
150.St -p1003.1-2008 .
151