The Manual on Extentions to the C Language Family

[Fergus Henderson]

On 03-Jan-2001, Hideaki Hase <hase@mech.usp.ac.jp> wrote:
> In the 9th par. in "Nested Functions,"
> a nested function always has NO linkage, rather than internal one,
> doesn't it?  An auto objects must have no linkage.

Yes.

However, it's not quite the same as the ordinary case of "no linkage",
since forward declarations are allowed.  It's more like the case of
struct tags, for which there is a special exception:

 |        6.7  Declarations
 ...
 |        [#3] If an identifier has no linkage, there shall be no more
 |        than one declaration of the identifier (in a  declarator  or
 |        type  specifier)  with  the  same scope and in the same name
 |        space, except for tags as specified in 6.7.2.3.

BTW, GNU C seems to allow nested functions to be declared `static', e.g.

	typedef void (*funcptr)(void);
        funcptr outer() {
                static void inner2();
                static void inner1() {
                        inner2();
                }
                static void inner2() {
                        /* ... */
                }
		inner1();
		return inner2;
        }

but the section on nested functions in the manual doesn't document
what this means.

-- 
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  of excellence is a lethal habit"
WWW: < http://www.cs.mu.oz.au/~fjh >  |     -- the last words of T. S. Garp.