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! 2: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>3. Introducing lists</title><link rel="stylesheet" type="text/css" href="tutorial.css" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><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"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="idm56"></a>3. Introducing lists</h2></div></div></div><p>
1.1 misho 3: That was easy. Now let's extend the program a bit so we can greet more than one
4: "target". We'd like to be able to specify a list of targets to greet.
5: </p><p>
6: The list versions of the initialization macros are named
7: <code class="function">CFG_STR_LIST()</code>,
8: <code class="function">CFG_INT_LIST()</code>,
9: <code class="function">CFG_BOOL_LIST()</code> and
10: <code class="function">CFG_FLOAT_LIST()</code>. They take the same
11: parameters as the non-list versions, except the default value must
12: be a string surrounded by curly braces.
13: </p><p>
14: The modified program is shown below:
15: </p><a id="listing4"></a><pre class="programlisting">
16: 1 #include <stdio.h>
17: 2 #include <confuse.h>
18: 3
19: 4 int main(void)
20: 5 {
21: 6 cfg_opt_t opts[] =
22: 7 {
23: 8 CFG_STR_LIST("targets", "{World}", CFGF_NONE),
24: 9 CFG_INT("repeat", 1, CFGF_NONE),
25: 10 CFG_END()
26: 11 };
27: 12 cfg_t *cfg;
28: 13 int repeat;
29: 14 int i;
30: 15
31: 16 cfg = cfg_init(opts, CFGF_NONE);
32: 17 if(cfg_parse(cfg, "hello.conf") == CFG_PARSE_ERROR)
33: 18 return 1;
34: 19
35: 20 repeat = cfg_getint(cfg, "repeat");
36: 21 while(repeat--)
37: 22 {
38: 23 printf("Hello");
39: 24 for(i = 0; i < cfg_size(cfg, "targets"); i++)
40: 25 printf(", %s", cfg_getnstr(cfg, "targets", i));
41: 26 printf("!\n");
42: 27 }
43: 28
44: 29 cfg_free(cfg);
45: 30 return 0;
46: 31 }
47: 32
48: </pre><p>
49: Three things are a bit different here. First, the macro to
50: initialize the "targets" option is
51: <code class="function">CFG_STR_LIST()</code>. This tells libConfuse that
52: "targets" is a list of strings. Second, the default value in the
53: second parameter is surrounded by curly braces. This is needed to
54: indicate to libConfuse where the list of values ends.
55: </p><p>
56: The third change is in the printing of the greeting. First we print
57: the "Hello" string. Then we loop through all values found for the
58: "targets" option. The number of values is retrieved with the
59: <code class="function">cfg_size()</code> function. The string values are
60: then retrieved with <code class="function">cfg_getnstr()</code>, which is an
61: indexed version of <code class="function">cfg_getstr()</code>. In fact,
62: <code class="function">cfg_getstr()</code> is equivalent to
63: <code class="function">cfg_getnstr()</code> with an index of zero.
64: </p><p>
65: In the configuration file hello.conf, we can now specify a list of targets to
66: greet:
67: </p><pre class="programlisting">
68: # this is the configuration file for the hello program
69:
70: targets = {"Life", "Universe", "Everything"}
71: repeat = 1
72: </pre><p>
73: The output of the hello program, run with the above configuration file, is:
74: "Hello, Life, Universe, Everything!"
75: </p><p>
76: Again, if no targets were configured, the greeting would have been the standard
77: "Hello, World!".
1.1.1.2 ! misho 78: </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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