[boost] [ATTN: Beman Dawes] Re: How does boost::function deal with defaultarguments?

From: Jim Apple (japple_at_[hidden])
Date: 2003-12-26 18:48:18

Aside: Beman, here's an Intel bug to report.

David Abrahams wrote:
 > the compiler bug doesn't affect the usability of Boost.Function

I disagree.  I wouldn't be concerned if this error caused working code, 
but Doug pointed out some code that should fail at compile time that 
instead fails silently at runtime.

Is there really any worse type of usability error? 8-)

> and
> it interacts with *any* code which does function pointer/reference
> assignment.

I'm not sure I understand this statement.  If you mean it this file 
would compile (and cause the test to fail) for function 
pointer/reference, then I disagree.  The compilers I tested emmitted the 
proper errors for non boost::function use.

Example:
--------------------------------------------------------
void f(int = 0) {}
 

void (*g)(int) = f;
 

struct indirect {
   void (*call)();
   template<typename FType>
   void attempt(FType * p) {
     reinterpret_cast<FType *>(call)();
   }
   /*
   void attempt_fail() {
     reinterpret_cast<void (*)(int)>(call)();
   }
   */
   indirect(void (*p)(int)) : call(reinterpret_cast<void (*)()>(p)) {}
};
 

int main() {
   indirect x(f);
   x.attempt(f);
   //g();
}
--------------------------------------------------------

Uncommenting indirect::attempt_fail causes a "too few arguments" compile 
error, as does uncommenting g(). However, g++ 3.3.1 and icc 8 both pass 
this with no errors, with -strict_ansi and -pedantic, respectively.

Jim