etfn = (arg_resetfn*)myresetfn;
val-&gt;hdr.scanfn  = (arg_scanfn*)myscanfn;
val-&gt;hdr.checkfn = (arg_checkfn*)mycheckfn;
val-&gt;hdr.errorfn = (arg_errorfn*)myerrorfn;</PRE><H4>
Words of restraint</H4>
<P STYLE="margin-bottom: 0cm">Callbacks are part of the argtable
design to make it possible to add new argument data types in future
without changing the base argtable source code. Since they exist,
they may be exploited by the programmer for finer control of the
parsing and error validation but that was n