1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
<!DOCTYPE html>
<html>
<!-- Created by GNU Texinfo 7.1.1, https://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Line-Oriented Input (GNU Octave (version 10.3.0))</title>
<meta name="description" content="Line-Oriented Input (GNU Octave (version 10.3.0))">
<meta name="keywords" content="Line-Oriented Input (GNU Octave (version 10.3.0))">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta name="viewport" content="width=device-width,initial-scale=1">
<link href="index.html" rel="start" title="Top">
<link href="Concept-Index.html" rel="index" title="Concept Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="C_002dStyle-I_002fO-Functions.html" rel="up" title="C-Style I/O Functions">
<link href="Formatted-Output.html" rel="next" title="Formatted Output">
<link href="Simple-Output.html" rel="prev" title="Simple Output">
<style type="text/css">
<!--
a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
div.example {margin-left: 3.2em}
span:hover a.copiable-link {visibility: visible}
strong.def-name {font-family: monospace; font-weight: bold; font-size: larger}
-->
</style>
<link rel="stylesheet" type="text/css" href="octave.css">
</head>
<body lang="en">
<div class="subsection-level-extent" id="Line_002dOriented-Input">
<div class="nav-panel">
<p>
Next: <a href="Formatted-Output.html" accesskey="n" rel="next">Formatted Output</a>, Previous: <a href="Simple-Output.html" accesskey="p" rel="prev">Simple Output</a>, Up: <a href="C_002dStyle-I_002fO-Functions.html" accesskey="u" rel="up">C-Style I/O Functions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<h4 class="subsection" id="Line_002dOriented-Input-1"><span>14.2.3 Line-Oriented Input<a class="copiable-link" href="#Line_002dOriented-Input-1"> ¶</a></span></h4>
<p>To read from a file it must be opened for reading using <code class="code">fopen</code>.
Then a line can be read from the file using <code class="code">fgetl</code> as the following
code illustrates
</p>
<div class="example">
<div class="group"><pre class="example-preformatted">fid = fopen ("free.txt");
txt = fgetl (fid)
-| Free Software is needed for Free Science
fclose (fid);
</pre></div></div>
<p>This of course assumes that the file ‘<samp class="samp">free.txt</samp>’ exists and contains
the line ‘<samp class="samp">Free Software is needed for Free Science</samp>’.
</p>
<a class="anchor" id="XREFfgetl"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-fgetl"><span><code class="def-type"><var class="var">str</var> =</code> <strong class="def-name">fgetl</strong> <code class="def-code-arguments">(<var class="var">fid</var>)</code><a class="copiable-link" href="#index-fgetl"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-fgetl-1"><span><code class="def-type"><var class="var">str</var> =</code> <strong class="def-name">fgetl</strong> <code class="def-code-arguments">(<var class="var">fid</var>, <var class="var">len</var>)</code><a class="copiable-link" href="#index-fgetl-1"> ¶</a></span></dt>
<dd><p>Read characters from a file, stopping after a newline, or EOF,
or <var class="var">len</var> characters have been read.
</p>
<p>The characters read, excluding the possible trailing newline, are returned
as a string.
</p>
<p>If <var class="var">len</var> is omitted, <code class="code">fgetl</code> reads until the next newline
character.
</p>
<p>If there are no more characters to read, <code class="code">fgetl</code> returns −1.
</p>
<p>To read a line and return the terminating newline,
see <a class="pxref" href="#XREFfgets"><code class="code">fgets</code></a>.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFfgets">fgets</a>, <a class="ref" href="Formatted-Input.html#XREFfscanf">fscanf</a>, <a class="ref" href="Binary-I_002fO.html#XREFfread">fread</a>, <a class="ref" href="Opening-and-Closing-Files.html#XREFfopen">fopen</a>.
</p></dd></dl>
<a class="anchor" id="XREFfgets"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-fgets"><span><code class="def-type"><var class="var">str</var> =</code> <strong class="def-name">fgets</strong> <code class="def-code-arguments">(<var class="var">fid</var>)</code><a class="copiable-link" href="#index-fgets"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-fgets-1"><span><code class="def-type"><var class="var">str</var> =</code> <strong class="def-name">fgets</strong> <code class="def-code-arguments">(<var class="var">fid</var>, <var class="var">len</var>)</code><a class="copiable-link" href="#index-fgets-1"> ¶</a></span></dt>
<dd><p>Read characters from a file, stopping after a newline, or EOF,
or <var class="var">len</var> characters have been read.
</p>
<p>The characters read, including the possible trailing newline, are returned
as a string.
</p>
<p>If <var class="var">len</var> is omitted, <code class="code">fgets</code> reads until the next newline
character.
</p>
<p>If there are no more characters to read, <code class="code">fgets</code> returns −1.
</p>
<p>To read a line and discard the terminating newline,
see <a class="pxref" href="#XREFfgetl"><code class="code">fgetl</code></a>.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="Simple-Output.html#XREFfputs">fputs</a>, <a class="ref" href="#XREFfgetl">fgetl</a>, <a class="ref" href="Formatted-Input.html#XREFfscanf">fscanf</a>, <a class="ref" href="Binary-I_002fO.html#XREFfread">fread</a>, <a class="ref" href="Opening-and-Closing-Files.html#XREFfopen">fopen</a>.
</p></dd></dl>
<a class="anchor" id="XREFfskipl"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-fskipl"><span><code class="def-type"><var class="var">nlines</var> =</code> <strong class="def-name">fskipl</strong> <code class="def-code-arguments">(<var class="var">fid</var>)</code><a class="copiable-link" href="#index-fskipl"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-fskipl-1"><span><code class="def-type"><var class="var">nlines</var> =</code> <strong class="def-name">fskipl</strong> <code class="def-code-arguments">(<var class="var">fid</var>, <var class="var">count</var>)</code><a class="copiable-link" href="#index-fskipl-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-fskipl-2"><span><code class="def-type"><var class="var">nlines</var> =</code> <strong class="def-name">fskipl</strong> <code class="def-code-arguments">(<var class="var">fid</var>, Inf)</code><a class="copiable-link" href="#index-fskipl-2"> ¶</a></span></dt>
<dd><p>Read and skip <var class="var">count</var> lines from the file specified by the file
descriptor <var class="var">fid</var>.
</p>
<p><code class="code">fskipl</code> discards characters until an end-of-line is encountered
exactly <var class="var">count</var>-times, or until the end-of-file marker is found.
</p>
<p>If <var class="var">count</var> is omitted, it defaults to 1. <var class="var">count</var> may also be
<code class="code">Inf</code>, in which case lines are skipped until the end of the file.
This form is suitable for counting the number of lines in a file.
</p>
<p>Returns the number of lines skipped (end-of-line sequences encountered).
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFfgetl">fgetl</a>, <a class="ref" href="#XREFfgets">fgets</a>, <a class="ref" href="Formatted-Input.html#XREFfscanf">fscanf</a>, <a class="ref" href="Opening-and-Closing-Files.html#XREFfopen">fopen</a>.
</p></dd></dl>
</div>
<hr>
<div class="nav-panel">
<p>
Next: <a href="Formatted-Output.html">Formatted Output</a>, Previous: <a href="Simple-Output.html">Simple Output</a>, Up: <a href="C_002dStyle-I_002fO-Functions.html">C-Style I/O Functions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
</div>
</body>
</html>
|
