te.</P>
<H4>Defining an arg_xxx structure</H4>
<P STYLE="margin-bottom: 0.51cm">Every <I>arg_xxx</I> struct must
have an <I>arg_hdr</I> struct as its first data member. Internally,
argtable casts all <I>arg_xxx</I> structures to <I>arg_hdr</I>
structures, so it is imperative that <I>arg_hdr</I> be the first data
member. Argtable uses the information within it to cast the command
line option into the format required by GNU getopt which actually
does the parsing.</P>
<PRE CLASS="western">struct arg_xxx
   {
 