stdio/FreeBSD/getline.3

   1 .\" Copyright (c) 2009 David Schultz <das@FreeBSD.org>
   2 .\" All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\"
  13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23 .\" SUCH DAMAGE.
  24 .\"
  25 .\" $FreeBSD: src/lib/libc/stdio/getline.3,v 1.5 2012/03/29 05:02:12 eadler Exp $
  26 .\"
  27 .Dd November 30, 2010
  28 .Dt GETLINE 3
  29 .Os
  30 .Sh NAME
  31 .Nm getdelim ,
  32 .Nm getline
  33 .Nd get a line from a stream
  34 .Sh LIBRARY
  35 .Lb libc
  36 .Sh SYNOPSIS
  37 .In stdio.h
  38 .Ft ssize_t
  39 .Fn getdelim "char ** restrict linep" "size_t * restrict linecapp" "int delimiter" " FILE * restrict stream"
  40 .Ft ssize_t
  41 .Fn getline "char ** restrict linep" "size_t * restrict linecapp" " FILE * restrict stream"
  42 .Sh DESCRIPTION
  43 The
  44 .Fn getdelim
  45 function reads a line from
  46 .Fa stream ,
  47 delimited by the character
  48 .Fa delimiter .
  49 The
  50 .Fn getline
  51 function is equivalent to
  52 .Fn getdelim
  53 with the newline character as the delimiter.
  54 The delimiter character is included as part of the line, unless
  55 the end of the file is reached.
  56 .Pp
  57 The caller may provide a pointer to a malloced buffer for the line in
  58 .Fa *linep ,
  59 and the capacity of that buffer in
  60 .Fa *linecapp .
  61 These functions expand the buffer as needed, as if via
  62 .Fn realloc .
  63 If
  64 .Fa linep
  65 points to a
  66 .Dv NULL
  67 pointer, a new buffer will be allocated.
  68 In either case,
  69 .Fa *linep
  70 and
  71 .Fa *linecapp
  72 will be updated accordingly.
  73 .Sh RETURN VALUES
  74 The
  75 .Fn getdelim
  76 and
  77 .Fn getline
  78 functions return the number of characters written, excluding the
  79 terminating
  80 .Dv NUL
  81 character.
  82 The value \-1 is returned if an error occurs, or if end-of-file is reached.
  83 .Sh EXAMPLES
  84 The following code fragment reads lines from a file and
  85 writes them to standard output.
  86 The
  87 .Fn fwrite
  88 function is used in case the line contains embedded
  89 .Dv NUL
  90 characters.
  91 .Bd -literal -offset indent
  92 char *line = NULL;
  93 size_t linecap = 0;
  94 ssize_t linelen;
  95 while ((linelen = getline(&line, &linecap, fp)) > 0)
  96         fwrite(line, linelen, 1, stdout);
  97 .Ed
  98 .Sh ERRORS
  99 These functions may fail if:
 100 .Bl -tag -width Er
 101 .It Bq Er EINVAL
 102 Either
 103 .Fa linep
 104 or
 105 .Fa linecapp
 106 is
 107 .Dv NULL .
 108 .It Bq Er EOVERFLOW
 109 No delimiter was found in the first
 110 .Dv SSIZE_MAX
 111 characters.
 112 .El
 113 .Pp
 114 These functions may also fail due to any of the errors specified for
 115 .Fn fgets
 116 and
 117 .Fn malloc .
 118 .Sh SEE ALSO
 119 .Xr fgetln 3 ,
 120 .Xr fgets 3 ,
 121 .Xr malloc 3
 122 .Sh STANDARDS
 123 The
 124 .Fn getdelim
 125 and
 126 .Fn getline
 127 functions conform to
 128 .St -p1003.1-2008 .
 129 .Sh HISTORY
 130 These routines first appeared in
 131 .Fx 8.0 .
 132 .Sh BUGS
 133 There are no wide character versions of
 134 .Fn getdelim
 135 or
 136 .Fn getline .