[Main]
Name=GetIntArg
Type=Function
Subtype=Macro
Header Files=args.h
Definition=unsigned long GetIntArg (CESI &ap);
Real Definition=#define GetIntArg(p) ({register unsigned short __n=*(--(ESI)(p)); register unsigned long __s=0; while(__n--) __s=(__s<<8)+*(--(unsigned char*)(p)); (ESI)(p)--; __s;})
See Also=args.h/GetLongLongArg

[Description]
Returns the current argument of integer type.

[Explanation]
GetIntArg is a macro which returns the current integer argument
(pointed to by <I>ap</I>) and modifies <I>ap</I> to point to the next argument in
the argument list. So, each successive time GetIntArg is used, it returns the next
argument in the argument list. If the argument is a negative number (check the sign using
<A HREF="$$LINK(args.h/GetArgType)">GetArgType</A>), GetIntArg returns its absolute value.
See <A HREF="$$LINK(args.h/InitArgPtr)">InitArgPtr</A> for an example of usage.
Note that GetIntArg assumes that the current argument IS an integer, either positive
or negative (this may be checked using <A HREF="$$LINK(args.h/GetArgType)">GetArgType</A>). If this
is not true, the result of GetIntArg is unpredictable.
<BR><BR>
If the current argument type is a fraction, do the following to pick it:
<PRE>numerator = GetIntArg (ap);
ap++;
denominator = GetIntArg (ap);
</PRE>
i.e. pick two integers, with increasing argument pointer between two picks.
<BR><BR>
<B>Note:</B> It is not recommended to do something like
<PRE>a = GetIntArg (top_estack);
</PRE>
It works fine sometimes, but not always. GetIntArg
is a function-looking macro, with <B>changes</B> the value of its actual
argument. So, if you write the statement mentioned above,
you will also change the value of TIOS system variable <A HREF="$$LINK(estack.h/top_estack)">top_estack</A>,
which is not always a good idea. So, I strictly recommend using an auxiliary variable,
like in the following example:
<PRE>ESI argptr = top_estack;
...
a = GetIntArg (argptr);
</PRE>
Using this method, you will avoid unexpected changes of <A HREF="$$LINK(estack.h/top_estack)">top_estack</A>.
