C / C++ / MFC

{<br />
 bstr_t a(_T("Blah")), b(_T("Blah"));<br />
 Foo(a, b);<br />
}

#include < iostream >
using namespace std;

struct a  // our bstr_t (or rather _bstr_t)
{
 a(){
  cout << "a()" << endl;
  s_=0; }
 
 a(const char*s){
  cout << "a(const char*i)" << endl;
  s_ =(char*) malloc(strlen(s)+1);
  strcpy(s_, s); }
 
 const a& operator= (const a& rhs){
   cout << "operator =" << endl;
   // do nothing. just to show this is not called
   return *this; }
 
 ~a(){
  cout << "~a()" << endl;
  free(s_); }
 operator char* () {return s_;}
private:
 char* s_;
};


typedef char MYCHAR;  // our char -> OLECHAR
typedef MYCHAR* MYCHARPTR; // our OLECHAR* -> BSTR


void func (MYCHARPTR n, MYCHARPTR m)
{
 cout << n << " " << m << endl;
}

int main( void )
{
 func( (MYCHARPTR)"Test cast", (MYCHARPTR)"from const char* to BSTR");
 func( (a)"Test cast", (a)"from const char* to BSTR wrapper class");
 func( a("Test constructing"), a("from const char* to BSTR wrapper class"));
 return 0;
}