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<h5 class="subsubsection">25.3.11.2 A Program Using Argp with Only Default Options</h5>

<p>This program doesn't use any options or arguments, it uses argp to be
compliant with the GNU standard command line format.

   <p>In addition to giving no arguments and implementing a &lsquo;<samp><span class="samp">--help</span></samp>&rsquo;
option, this example has a &lsquo;<samp><span class="samp">--version</span></samp>&rsquo; option, which will put the
given documentation string and bug address in the &lsquo;<samp><span class="samp">--help</span></samp>&rsquo; output,
as per GNU standards.

   <p>The variable <code>argp</code> contains the argument parser
specification.  Adding fields to this structure is the way most
parameters are passed to <code>argp_parse</code>.  The first three fields are
normally used, but they are not in this small program.  There are also
two global variables that argp can use defined here,
<code>argp_program_version</code> and <code>argp_program_bug_address</code>.  They
are considered global variables because they will almost always be
constant for a given program, even if they use different argument
parsers for various tasks.

<pre class="smallexample">     /* <span class="roman">Argp example #2 -- a pretty minimal program using argp</span> */
     
     /* <span class="roman">This program doesn't use any options or arguments, but uses
        argp to be compliant with the GNU standard command line
        format.
     
        In addition to making sure no arguments are given, and
        implementing a --help option, this example will have a
        --version option, and will put the given documentation string
        and bug address in the --help output, as per GNU standards.
     
        The variable ARGP contains the argument parser specification;
        adding fields to this structure is the way most parameters are
        passed to argp_parse (the first three fields are usually used,
        but not in this small program).  There are also two global
        variables that argp knows about defined here,
        ARGP_PROGRAM_VERSION and ARGP_PROGRAM_BUG_ADDRESS (they are
        global variables because they will almost always be constant
        for a given program, even if it uses different argument
        parsers for various tasks).</span> */
     
     #include &lt;argp.h&gt;
     
     const char *argp_program_version =
       "argp-ex2 1.0";
     const char *argp_program_bug_address =
       "&lt;bug-gnu-utils@gnu.org&gt;";
     
     /* <span class="roman">Program documentation.</span> */
     static char doc[] =
       "Argp example #2 -- a pretty minimal program using argp";
     
     /* <span class="roman">Our argument parser.  The </span><code>options</code><span class="roman">, </span><code>parser</code><span class="roman">, and
        </span><code>args_doc</code><span class="roman"> fields are zero because we have neither options or
        arguments; </span><code>doc</code><span class="roman"> and </span><code>argp_program_bug_address</code><span class="roman"> will be
        used in the output for &lsquo;</span><samp><span class="samp">--help</span></samp><span class="roman">&rsquo;, and the &lsquo;</span><samp><span class="samp">--version</span></samp><span class="roman">&rsquo;
        option will print out </span><code>argp_program_version</code><span class="roman">.</span> */
     static struct argp argp = { 0, 0, 0, doc };
     
     int main (int argc, char **argv)
     {
       argp_parse (&amp;argp, argc, argv, 0, 0, 0);
       exit (0);
     }
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