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<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!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=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> That was easy. Now let's extend the program a bit so we can greet more than one "target". We'd like to be able to specify a list of targets to greet. </p><p> The list versions of the initialization macros are named <code class="function">CFG_STR_LIST()</code>, <code class="function">CFG_INT_LIST()</code>, <code class="function">CFG_BOOL_LIST()</code> and <code class="function">CFG_FLOAT_LIST()</code>. They take the same parameters as the non-list versions, except the default value must be a string surrounded by curly braces. </p><p> The modified program is shown below: </p><a id="listing4"></a><pre class="programlisting"> 1 #include <stdio.h> 2 #include <confuse.h> 3 4 int main(void) 5 { 6 cfg_opt_t opts[] = 7 { 8 CFG_STR_LIST("targets", "{World}", CFGF_NONE), 9 CFG_INT("repeat", 1, CFGF_NONE), 10 CFG_END() 11 }; 12 cfg_t *cfg; 13 int repeat; 14 int i; 15 16 cfg = cfg_init(opts, CFGF_NONE); 17 if(cfg_parse(cfg, "hello.conf") == CFG_PARSE_ERROR) 18 return 1; 19 20 repeat = cfg_getint(cfg, "repeat"); 21 while(repeat--) 22 { 23 printf("Hello"); 24 for(i = 0; i < cfg_size(cfg, "targets"); i++) 25 printf(", %s", cfg_getnstr(cfg, "targets", i)); 26 printf("!\n"); 27 } 28 29 cfg_free(cfg); 30 return 0; 31 } 32 </pre><p> Three things are a bit different here. First, the macro to initialize the "targets" option is <code class="function">CFG_STR_LIST()</code>. This tells libConfuse that "targets" is a list of strings. Second, the default value in the second parameter is surrounded by curly braces. This is needed to indicate to libConfuse where the list of values ends. </p><p> The third change is in the printing of the greeting. First we print the "Hello" string. Then we loop through all values found for the "targets" option. The number of values is retrieved with the <code class="function">cfg_size()</code> function. The string values are then retrieved with <code class="function">cfg_getnstr()</code>, which is an indexed version of <code class="function">cfg_getstr()</code>. In fact, <code class="function">cfg_getstr()</code> is equivalent to <code class="function">cfg_getnstr()</code> with an index of zero. </p><p> In the configuration file hello.conf, we can now specify a list of targets to greet: </p><pre class="programlisting"> # this is the configuration file for the hello program targets = {"Life", "Universe", "Everything"} repeat = 1 </pre><p> The output of the hello program, run with the above configuration file, is: "Hello, Life, Universe, Everything!" </p><p> Again, if no targets were configured, the greeting would have been the standard "Hello, World!". </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>