------- Additional Comments From joseph at codesourcery dot com 2005-04-13 20:42 ------- Subject: Re: bogus error passing &va_list to va_list*
On Mon, 11 Apr 2005, sebor at roguewave dot com wrote: > Yes, I read that comment but I still don't see anything in the standard the > footnote is in conflict with and I don't see it on the WG14 DR list(*). If the > footnote is bogus and va_list can't be universally implemented to allow > programs > to initialize a va_list* with the address of a va_list function argument,it > ought to be taken out of the standard. If you are not aware of an issue > against > the C standard I'll be happy to send it to the committee myself. I see nothing wrong with the footnote. You can create a pointer to a va_list, as the footnote notes. To do so, you need an object of type va_list. Declaring a function parameter as "va_list va" doesn't declare such a object if va_list is an array type; it declares one of type "va_list_member *" where va_list is an array va_list_member[number_of_elements]. Just because it says you can create a pointer doesn't mean you can do so with "&va" if va doesn't have va_list type, any more that it means you can do so with "random expression I'd like to have va_list * type but which has nothing to do with va_list"; they are in exactly the same position. If your expression has type va_list * according to the semantics of the language and is the address of a va_list object, you can use it. (comment#1 in this bug is bogus. &va isn't &va[0], it's the address of the pointer argument rather than the address of an element. Both of these are of course different from the address of the va_list object itself which has type va_list * (i.e. va_list_member (*)[number_of_elements]) instead of va_list_member ** (which &va has) or va_list_member * (which &va[0] has). comment#8 in bug 14557 is just confused as well; ignore it and read comments 10-14 instead.) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20951
