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Revision 1.1.1.2 (vendor branch): download - view: text, annotated - select for diffs - revision graph
Wed Mar 17 00:49:17 2021 UTC (3 years, 3 months ago) by misho
Branches: confuse, MAIN
CVS tags: v3_3, HEAD
confuse 3.3

    1: <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    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>
    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 &lt;stdio.h&gt;
   17: 2	#include &lt;confuse.h&gt;
   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 &lt; 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!".
   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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