.\"	$OpenBSD: getdelim.3,v 1.7 2022/12/20 17:59:29 schwarze Exp $
.\"     $NetBSD: getdelim.3,v 1.9 2011/04/20 23:37:51 enami Exp $
.\"
.\" Copyright (c) 2009 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Roy Marples.
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.Dd $Mdocdate: December 20 2022 $
.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 ,
storing the input in
.Fa *lineptr .
The buffer is
.Dv NUL Ns No -terminated
and includes the delimiter.
The
.Fa delimiter
character must be representable as an
.Vt 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
will
.Xr realloc 3
.Fa *lineptr
as necessary, updating
.Fa *n
to reflect the new size.
It is the responsibility of the caller to
.Xr free 3
.Fa *lineptr
when it is no longer needed.
Even when it fails,
.Fn getdelim
may update
.Fa *lineptr .
.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 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(\*[Am]line, \*[Am]linesize, fp)) != -1)
	fwrite(line, linelen, 1, stdout);

free(line);
if (ferror(fp))
	err(1, "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
.Sh STANDARDS
The
.Fn getdelim
and
.Fn getline
functions conform to
.St -p1003.1-2008 .
.Sh HISTORY
These functions were ported from
.Nx
to
.Ox 5.2 .