Re: [Boost-users] trouble with enable_if

31 Aug 2007


      Neal Becker wrote:
...
The following code:
template<typename int_t>
inline typename boost::enable_if_c::value,
std::complex >::value operator >> (std::complex const&x, int
bits) {
  return std::complex (real (x) >> bits, imag (x) >> bits);
}
// template<typename int_t>
// inline std::complex
// operator >> (std::complex const&x, int bits) {
//   return std::complex (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?
I figured it out, this works:
template<typename int_t>
inline typename boost::enable_if, std::complex >::type
operator >> (std::complex const&x, int bits) {
  return std::complex (real (x) >> bits, imag (x) >> bits);
}