.\"     $NetBSD: getdelim.3,v 1.15 2017/07/03 21:32:49 wiz Exp $
.\"
.\" Copyright (c) 2009 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Roy Marples.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd September 15, 2014
.Dt GETDELIM 3
.Os
.Sh NAME
.Nm getdelim ,
.Nm getline
.Nd read a delimited record from a stream
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdio.h
.Ft ssize_t
.Fn getdelim "char ** restrict lineptr" "size_t * restrict n" "int delimiter" "FILE * restrict stream"
.Ft ssize_t
.Fn getline "char ** restrict lineptr" "size_t * restrict n" "FILE * restrict stream"
.Sh DESCRIPTION
The
.Fn getdelim
function reads from the
.Fa stream
until it encounters a character matching
.Fa delimiter
or
.Dv EOF ,
storing the input in
.Fa *lineptr .
The buffer is
.Dv NUL Ns No -terminated
and includes the delimiter, if one was found.
The
.Fa delimiter
character must be representable as an unsigned char.
.Pp
If
.Fa *n
is non-zero, then
.Fa *lineptr
must be pre-allocated to at least
.Fa *n
bytes.
The buffer should be allocated dynamically;
it must be possible to
.Xr free 3
.Fa *lineptr .
.Fn getdelim
ensures that
.Fa *lineptr
is large enough to hold the input, updating
.Fa *n
to reflect the new size.
.Pp
The
.Fn getline
function is equivalent to
.Fn getdelim
with
.Fa delimiter
set to the newline character.
.Sh RETURN VALUES
The
.Fn getdelim
and
.Fn getline
functions return the number of characters read, including the delimiter if
one was found.
If no characters were read and the stream is at end-of-file, the functions
return \-1.
If an error occurs, the functions return \-1 and the global variable
.Va errno
is set to indicate the error.
.Pp
The functions do not distinguish between end-of-file and error,
and callers must use
.Xr feof 3
and
.Xr ferror 3
to determine which occurred.
.Sh EXAMPLES
The following code fragment reads lines from a file and writes them to
standard output.
.Bd -literal -offset indent
char *line = NULL;
size_t linesize = 0;
ssize_t linelen;

while ((linelen = getline(&line, &linesize, fp)) != -1)
	fwrite(line, linelen, 1, stdout);

if (ferror(fp))
	perror("getline");
.Ed
.Sh ERRORS
.Bl -tag -width [EOVERFLOW]
.It Bq Er EINVAL
.Fa lineptr
or
.Fa n
is a
.Dv NULL
pointer.
.It Bq Er EOVERFLOW
More than SSIZE_MAX characters were read without encountering the delimiter.
.El
.Pp
The
.Fn getdelim
and
.Fn getline
functions may also fail and set
.Va errno
for any of the errors specified in the routines
.Xr fflush 3 ,
.Xr malloc 3 ,
.Xr read 2 ,
.Xr stat 2 ,
or
.Xr realloc 3 .
.Sh SEE ALSO
.Xr ferror 3 ,
.Xr fgets 3 ,
.Xr fopen 3 ,
.Xr strlen 3
.Sh STANDARDS
The
.Fn getdelim
and
.Fn getline
functions conform to
.St -p1003.1-2008 .
.Sh NOTES
The
.Fn getdelim
and
.Fn getline
functions can return results that include
.Dv NUL
characters, which can cause the apparent length reported by
.Xr strlen 3
to be less than the true length reported by the
return values of the functions.