How to monitor quad_qags error codes for the inner integral?

I am so far not successful in trying to use quad_qags
for a double integral in which I monitor the error 
code returned by the inner integral:

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Maxima 5.25.1 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)


(%i1) float(integrate(integrate(x*y^2,y,0,1),x,0,1));

(%o1) 0.16666666666667

(%i2) quad_qags(quad_qags(x*y^2,y,0,1)[1],x,0,1);

(%o2) [0.16666666666667,1.8503717077085952E-15,21,0]

(%i3) qarea(ex,uL,vL) :=

   block([%%u,u1,u2,%%v,v1,v2,%uu,verrL:[],
               %ruL,%uans,%uerr,
        exu : buildq([%%u,ex,v1,v2,%%v,verrL],lambda([u0],
                   block([%expr,%v1,%v2,%rL,%ans,%errcode],
                        %expr:subst(u0,%%u,ex),
                        %v1:subst(u0,%%u,v1),
                        %v2:subst(u0,%%u,v2),
                        %rL:quad_qags(%expr,%%v,%v1,%v2),
                        %ans : part(%rL,1),
                        %errcode : part(%rL,4),
                        if %errcode # 0 then verrL : cons(%errcode,verrL),
                        %ans)))],

        [%%u,u1,u2] : uL,
        [%%v,v1,v2] : vL,

        display(%%u,u1,u2,%%v,v1,v2),
        print (" exu(0.5) = ",exu(0.5)),

        %ruL : quad_qags(exu(%uu),%uu,u1,u2,limit=700),
       display(%ruL),

        if not listp(%ruL) then
               (print(" %ruL is not a list"),return(false)),

         %uans : part(%ruL,1),
         %uerr : part(%ruL,4),
         if length(verrL) > 0 then
         print("internal integral error code(s) = ", verrL),

         if %uerr # 0 then
               print(" external integral error code = ",%uerr),

         %uans)$

(%i4) qarea (x*y^2, [x,0,1], [y,0,1] );

%%u = x

u1 = 0

u2 = 1

%%v = y

v1 = 0

v2 = 1

 exu(0.5) =  0.16666666666667

%ruL = quad_qags(%uu*y^2,%uu,0,1,epsrel = 1.0E-8,epsabs = 0.0,limit = 700)

 %ruL is not a list

(%o4) false
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Any suggestions about how I can make this work or use
another tactic?

Ted Woollett