linux下编程用 编译软件

				// { dg-do assemble  }				// { dg-options "-Wconversion" } 				// Test that we resolve this case as mandated by the standard, but also				// warn about it.  We choose op char* not because it is a member of B --				// the standard says that all conversion ops are treated as coming from				// the type of the argument -- but because it is non-const.								struct A  {				  operator const char *() const { return ""; }				};								struct B : public A {				  operator char *() { return 0; }				};								int main()				{				  B b;				  if ((const char *)b != 0)  // { dg-warning "" } surprising overload resolution				    return 1;				  if ((const char *)(const B)b == 0)				    return 2;				  if ((const char *)(const B &)b == 0)				    return 3;				}