This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: g++4.0 diagnostic on casting a static const member initializerto a double


Fariborz Jahanian wrote:
g++ 4.0 in FSF issues a diagnostic on the following test case:

template <class T> struct S {
  static const double scd = (double)24;
};

test1.C:2: error: a cast to a type other than an integral or enumeration type cannot appear in a constant-expression

Rewriting the above to:

template <class T> struct S {
  static const double scd;
};

template <class T>
const double S<T>::scd = (double)24;

Compiles. Event though the diagnostic is clear in what it is saying, but it seems to be a g++ bug
one way or the other.

No, the input program is invalid. From [class.static.data]:


"If a static data member is of const integral or const enumeration type, its declaration in the class definition can specify a constant-initializer which shall be an integral constant expression(_expr.const_)."

The diagnostic could be better, but it is indeed accurate; if there's an initializer it must be integral constant-expression, and a cast to "double" cannot appear in such an expression.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]