Re: Style convention question

[Owen Taylor <otaylor redhat com>]

Derek Simkowiak <dereks realloc net> writes:

> 	This is a quickie.  My apologies if it's not the best list for
> this, but I know that the right people are here :).
> 
> 	Why does Glib do this:
> 
> typedef struct _GFoo GFoo;
> struct _GFoo {
> 	/* [...] */
> };
> 
> 	...instead of the more compact
> 
> typedef struct {
> 	/* [...] */
> } GFoo;
> 
> 	I don't see the "struct _GFoo"s anywhere in the code.  I asked a
> veteran Unix programmer and he didn't know of any compilers that had
> problems with the "typedef struct { /* stuff */ } GFoo;" format.
> 
> 	Is this just a religous thing?  Or is there some
> backwater-compiler that doesn't support the latter format?

The reason is that sometimes you need forward declarations:

 typedef struct _A A;
 typedef struct _B B;

 struct _A {
   B *b;
 };

 struct _B {
   A *a;
 };

And instead of worrying about the order of structure definitions, and
what ones need to be forward declared and what ones don't, we, by
convention, forward declare everything.

Regards,
                                        Owen