t;
   void *parent;
   <B>arg_resetfn *resetfn;</B>
   <B>arg_scanfn  *scanfn; </B>
   <B>arg_checkfn *checkfn;</B>
   <B>arg_errorfn *errorfn;</B>
   <FONT COLOR="#000000">void *priv;</FONT><FONT COLOR="#666666"> </FONT>
   };</PRE><P STYLE="margin-bottom: 0cm">
These function pointers are always pre-set by the <I>arg_xxx</I>
constructor functions to the default routines for that argument type
and ordinarily there is no need to change them. However, you may
replace them with your own custom routines if you