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3: <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>3. Introducing lists</title><link rel="stylesheet" href="tutorial.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="libConfuse tutorial" /><link rel="up" href="index.html" title="libConfuse tutorial" /><link rel="prev" href="ar01s02.html" title="2. Other types of options" /><link rel="next" href="ar01s04.html" title="4. Using sections" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">3. Introducing lists</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s02.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s04.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="3. Introducing lists"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="id401321"></a>3. Introducing lists</h2></div></div></div><p>
4: That was easy. Now let's extend the program a bit so we can greet more than one
5: "target". We'd like to be able to specify a list of targets to greet.
6: </p><p>
7: The list versions of the initialization macros are named
8: <code class="function">CFG_STR_LIST()</code>,
9: <code class="function">CFG_INT_LIST()</code>,
10: <code class="function">CFG_BOOL_LIST()</code> and
11: <code class="function">CFG_FLOAT_LIST()</code>. They take the same
12: parameters as the non-list versions, except the default value must
13: be a string surrounded by curly braces.
14: </p><p>
15: The modified program is shown below:
16: </p><a id="listing4"></a><pre class="programlisting">
17: 1 #include <stdio.h>
18: 2 #include <confuse.h>
19: 3
20: 4 int main(void)
21: 5 {
22: 6 cfg_opt_t opts[] =
23: 7 {
24: 8 CFG_STR_LIST("targets", "{World}", CFGF_NONE),
25: 9 CFG_INT("repeat", 1, CFGF_NONE),
26: 10 CFG_END()
27: 11 };
28: 12 cfg_t *cfg;
29: 13 int repeat;
30: 14 int i;
31: 15
32: 16 cfg = cfg_init(opts, CFGF_NONE);
33: 17 if(cfg_parse(cfg, "hello.conf") == CFG_PARSE_ERROR)
34: 18 return 1;
35: 19
36: 20 repeat = cfg_getint(cfg, "repeat");
37: 21 while(repeat--)
38: 22 {
39: 23 printf("Hello");
40: 24 for(i = 0; i < cfg_size(cfg, "targets"); i++)
41: 25 printf(", %s", cfg_getnstr(cfg, "targets", i));
42: 26 printf("!\n");
43: 27 }
44: 28
45: 29 cfg_free(cfg);
46: 30 return 0;
47: 31 }
48: 32
49: </pre><p>
50: Three things are a bit different here. First, the macro to
51: initialize the "targets" option is
52: <code class="function">CFG_STR_LIST()</code>. This tells libConfuse that
53: "targets" is a list of strings. Second, the default value in the
54: second parameter is surrounded by curly braces. This is needed to
55: indicate to libConfuse where the list of values ends.
56: </p><p>
57: The third change is in the printing of the greeting. First we print
58: the "Hello" string. Then we loop through all values found for the
59: "targets" option. The number of values is retrieved with the
60: <code class="function">cfg_size()</code> function. The string values are
61: then retrieved with <code class="function">cfg_getnstr()</code>, which is an
62: indexed version of <code class="function">cfg_getstr()</code>. In fact,
63: <code class="function">cfg_getstr()</code> is equivalent to
64: <code class="function">cfg_getnstr()</code> with an index of zero.
65: </p><p>
66: In the configuration file hello.conf, we can now specify a list of targets to
67: greet:
68: </p><pre class="programlisting">
69: # this is the configuration file for the hello program
70:
71: targets = {"Life", "Universe", "Everything"}
72: repeat = 1
73: </pre><p>
74: The output of the hello program, run with the above configuration file, is:
75: "Hello, Life, Universe, Everything!"
76: </p><p>
77: Again, if no targets were configured, the greeting would have been the standard
78: "Hello, World!".
79: </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s02.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="ar01s04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">2. Other types of options </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 4. Using sections</td></tr></table></div></body></html>
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