[Boost-users] trouble with enable_if

From: Neal Becker (ndbecker2_at_[hidden])
Date: 2007-08-31 08:54:55

The following code:

template<typename int_t>
inline typename boost::enable_if_c<boost::is_integral<int_t>::value, std::complex<int_t> >::value
operator >> (std::complex<int_t> const&x, int bits) {
  return std::complex<int_t> (real (x) >> bits, imag (x) >> bits);
}

// template<typename int_t>
// inline std::complex<int_t>
// operator >> (std::complex<int_t> const&x, int bits) {
//   return std::complex<int_t> (real (x) >> bits, imag (x) >> bits);
// }

int main() {
 std::cout << (x >> 1) << '\n';
}

gives:
error: no match for 'operator>>' in 'x >> 1' (gcc-4.1.2)

Uncomment the commented out version (without enable_if) and it compiles.  What's wrong here?