SV* test( SV *a, SV *b ) {
    SV * c;
    if(SvREADONLY(a)) {
      c = newSVsv(a);
      sv_catsv(c, b);
      return c;
      }

    sv_catsv(a,b);
    c = newSVsv(a);
    return c;
}

##</code><code>##

SV * test4(SV * a, SV * b){return newSVuv(42);}
SV * test5(char * a, char * b){return newSVuv(42);}