copy constructor not being called

Hi

In the following code, I expect the copy constructor to be called as
per the textbooks but it is not being called. Could you please tell me
why? g++ version 4.1.2

# include <iostream>
using namespace std;
class base
{
   char s;
public:
   base( ){cout<< "construction" << endl;}
   base(const char a ) {cout << "construction with arg" << endl;}
   base(const base & a){cout <<"copy constructor" << endl;}
   base & operator=(const base & a){cout << "assignment operator" <<
endl;}
   ~base( ) {cout << "destruction" << endl;}
};

main ( )
{
   base b1 = 'x'; //why copy constructor not called here?
   base b2 = b1; //copy constructor is called
}

the line base b1 = 'x', as per my understanding must create a
temporary object and then it should be copied to b1. But only the
constructor with argument is called in this example when executed.

Could you please explain why?

thanks and regards
suresh


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