xref: /netbsd-src/lib/libc/stdio/getdelim.3 (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1.\"     $NetBSD: getdelim.3,v 1.8 2010/06/30 13:38:10 jruoho Exp $
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3.\" Copyright (c) 2009 The NetBSD Foundation, Inc.
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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 June 30, 2010
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
51.Fa delimiter ,
52storing the input in
53.Fa *lineptr .
54The buffer is
55.Dv NUL Ns No -terminated
56and includes the delimiter.
57The
58.Fa delimiter
59character must be representable as an unsigned char.
60.Pp
61If
62.Fa *n
63is non-zero, then
64.Fa *lineptr
65must be pre-allocated to at least
66.Fa *n
67bytes.
68The buffer should be allocated dynamically;
69it must be possible to
70.Xr free 3
71.Fa *lineptr .
72.Fn getdelim
73ensures that
74.Fa *lineptr
75is large enough to hold the input, updating
76.Fa *n
77to reflect the new size.
78.Pp
79The
80.Fn getline
81function is equivalent to
82.Fn getdelim
83with
84.Fa delimiter
85set to the newline character.
86.Sh RETURN VALUES
87The
88.Fn getdelim
89and
90.Fn getline
91functions return the number of characters read, including the delimiter.
92If no characters were read and the stream is at end-of-file, the functions
93return \-1.
94If an error occurs, the functions return \-1 and the global variable
95.Va errno
96is set to indicate the error.
97.Pp
98The functions do not distinguish between end-of-file and error,
99and callers must use
100.Xr feof 3
101and
102.Xr ferror 3
103to determine which occurred.
104.Sh EXAMPLES
105The following code fragment reads lines from a file and writes them to
106standard output.
107.Bd -literal -offset indent
108char *line = NULL;
109size_t linesize = 0;
110ssize_t linelen;
111while ((linelen = getline(\*[Am]line, \*[Am]linesize, fp)) != -1)
112	fwrite(line, linelen, 1, stdout);
113
114if (ferror(fp))
115	perror("getline");
116.Ed
117.Sh ERRORS
118.Bl -tag -width [EOVERFLOW]
119.It Bq Er EINVAL
120.Fa *lineptr
121or
122.Fa *n
123is a
124.Dv NULL
125pointer.
126.It Bq Er EOVERFLOW
127More than SSIZE_MAX characters were read without encountering the delimiter.
128.El
129.Pp
130The
131.Fn getdelim
132and
133.Fn getline
134functions may also fail and set
135.Va errno
136for any of the errors specified in the routines
137.Xr fflush 3 ,
138.Xr malloc 3 ,
139.Xr read 2 ,
140.Xr stat 2 ,
141or
142.Xr realloc 3 .
143.Sh SEE ALSO
144.Xr ferror 3 ,
145.Xr fgets 3 ,
146.Xr fopen 3
147.Sh STANDARDS
148The
149.Fn getdelim
150and
151.Fn getline
152functions conform to
153.St -p1003.1-2008 .
154