C++/CLI: System::String^ to std::string

/// Copies the contents of a managed System::String^ into a std::string
/**
 * @preconditions
 *    The provided managed string must be initialized.
 * @postconditions
 *    None
 * @param string
 *    The managed string to convert
 * @return
 *    A std::string created from the managed string
 * @throw
 *    This method will throw a NullReferenceException if the input is null
 */
static std::string toStandardString(System::String^ string)
{
     using System::Runtime::InteropServices::Marshal;
     System::IntPtr pointer = Marshal::StringToHGlobalAnsi(string);
     char* charPointer = reinterpret_cast<char*>(pointer.ToPointer());
     std::string returnString(charPointer, string->Length);
     Marshal::FreeHGlobal(pointer);
     return returnString;
}