Re: references to functions

From:
Barry <dhb2000@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 01 Jan 2008 19:25:30 +0800
Message-ID:
<fldcjm$hq6$1@news.cn99.com>
Rahul wrote:

On Jan 1, 2:02 pm, Barry <dhb2...@gmail.com> wrote:

Rahul wrote:

Hi Everyone,
 I was wondering about references to functions, so i tried this,
int (& p[10]) (); // doesn't work as array of references is
illegal as memory is not allocated for references,
next, i tried a single reference to the function,
int ( & p ) ();
int incomplete_function(void)
{
// #error *** Nigel - Function incomplete. Fix before using ***
   printf("testing testing testing done...\n");
   return (0);
}
int sample(void)
{
   printf("sample\n");
   return(0);
}
int main()
{
   int ( & p) ();
   p = incomplete_function;
        p();
   p = sample;
   p();
   return(0);
}
and it works fine and both the functions are called, but i expected
the reference to be a constant pointer which can't be declared, in
fact i expected a compilation error in the declaration of the
reference p as it is not initialized over here, is reference to
function legal? what does the standard say about this?

<std>
8.3.5/6
... There shall be no arrays of functions, although there can
be arrays of pointers to functions.
</std>

"Reference to function" is legal, but no "array of function", then of
course, no "reference to array of function".


Yes i understand that there can't be any array of references, i was
asking about a reference to the function and the fact that it can be
changed during the execution...


In this case you couldn't use reference to function, as you can't change
the what the reference refers to after the reference is
bound(initialized) to some object. Use pointer to function instead.

void foo() {}
void bar() {}

typedef void FT();

int main()
{
   FT* pf;

   pf = foo;
   pf();

   pf = bar;
   pf();
}

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